Most of us know what Kosher means, so I won't bore you with an explanation of that.  When Jews, and others, "keep Kosher" it simply means one is adhering to the rules of slaughter, what's allowed and what's not, no pork, etc.  Very few, from what I gather, observe true Kosher.  Heck, even Rabbis don't "bless" meat in the right manner allowing for some pork and/or pork-by-products.

Guess what?  Muslims too create their own confusion; when there really doesn't need to be any.

Let's establish a few facts:
At the time of the Prophet (pbuh), the Christians and Jews of his time were not too different from today's.  Different versions of the Bible existed then, and they still exist now  —Many, we believe, are man-altered.  Yet, during the Prophet's time and still to this day, we Muslims call our fellow Christians and Jews People of The Book.  They are sister/cousin religions of Islam.  We Muslims can marry from amongst People of The Book, and ... we can eat what they eat, unlike other beliefs, as long as it does not conflict with what we permit; specifically, pork and fermented drinks (alcohol)  —As long as it's "halal."

Halal, literally, means permissible or allowed.  It is halal for me as a Muslim man to marry a Christian woman.  It is haram (not allowed/permissible) for a Muslim woman to marry a non-Muslim man.  It is haram for me as a Muslim man to marry a woman that's not from the People of The Book.  You get the idea.

Before I proceed, allow me to interject and seize this opportunity, as I have in the past, and say:
It's an article of faith, a requirement for Muslims, to believe in Jesus (pbuh), his miraculous birth, his mother the virgin Mary (pbuh) and in his return as well. The Qur'an has more on Jesus, his mother and her family than the Torah and the Bible combined.  Yes, Muslims believe in Jesus.  Don't let the media so easily sway you.

Back to the topic ... The owner of 4islam.com, a site that's unfortunately rarely updated but still contains good information, once had a sister site called halaleats.com (a site no longer in circulation).  In it was the following:

Halal is an Arabic word meaning lawful or permitted. The opposite of halal is haram, which means unlawful or prohibited. Halal and haram are universal terms that apply to all facets of life. However, we will use these terms only in relation to food products, meat products, cosmetics, personal care products, food ingredients, and food contact materials.
While many things are clearly Halal or clearly haram, there are some things which are not clear. These items are considered questionable or suspect and more information is needed to categorize them as Halal or haram. Such items are often referred to as Mashbooh, which means doubtful or questionable.

All foods are considered Halal except the following, which are haram:

• Swine/pork and its by-products
• Animals improperly slaughtered or dead before slaughtering
• Animals killed in the name of anyone other than ALLAH (God)
• Alcohol and intoxicants
• Carnivorous animals, birds of prey and land animals without external ears
• Blood and blood by-products
• Foods contaminated with any of the above products

Foods containing ingredients such as gelatin, enzymes, emulsifiers, etc. are questionable (Mashbooh) because the origin of these ingredients is not known.

The following products are definitely Halal:

1. Milk (from cows, sheep, camels, and goats)
2. Honey
3. Fish
4. Plants which are not intoxicant
5. Fresh or naturally frozen vegetables
6. Fresh or dried fruits
7. Legumes and nuts like peanuts, cashew nuts, hazel nuts, walnuts, etc.
8. Grains such as wheat, rice, rye, barley, oat, etc.

The same site contained information, which I had saved and cannot seem to get the Way Back Machine to link to, regarding Thabiha.
Thabiha, mistakingly spelled Zabiha since the Indo-Pak Muslims cannot seem to pronounce the sound "th" as in the word "that" when it comes to Islamic terms, is best described as Islamically slaughtered meat.  You can find out more about thabiha here.

If it's thabiha, it's halal.  Halal, however, does not mean thabiha.  Separately, kosher does not necessarily mean halal either.
Allow me to explain:  Cow meat (beef) slaughtered Islamically is called thabiha and is therefore halal; and aside from the specific Rabbi "blessing," it would also be considered kosher.  The same beef slaughtered by People of The Book, according to Islam, is considered halal; but since it wasn't slaughtered Islamically it's not thabiha.  By default, all halal meat (again minus the actual "blessings" of a Rabbi) are kosher.

The same site, halaleats.com, had re-published an article called "Thabiha or Non-Thabiha: Three Scholarly Opinions."  The same article, sans the correct spelling, can be found here.  It's really worth reading.  For my non-Muslim readers, I ask this ... Know that "Allah" is the word for God.  There are reasons why Muslims insist on the use of the word "Allah" even when speaking in English, and to learn more about that, I ask that you read this.  For now, however, just substitute in your mind Allah = God (not Jesus, but God Himself).

Personally, I have accepted that things are permissible unless explicitly prohibited.  And unless I have heard or learned that a Christian or a Jew provoking another name than that of God when slaughtering, then it's permissible (halal) for me to eat from that slaughter.  What does that really mean?  It means if I hear someone slaughtering an animal and saying "in the name of Jesus" then it's haram for me to eat.  As Christians & Jews who normally don't  say "in the name of " when slaughtering, and since we Islamically recognize and accept them as People of The Book, as sisters or cousin religions, their monotheistic belief supersedes any assumptions  —The assumption that they, the People of The Book, would provoke and/or attribute the slaughter of any animal to another but God.

The point of contention, you see, is that we Muslims say "but they [Christians & Jews] say 'oh jeez' or 'Jesus this' or 'Jesus that' and hardly mention or believe in God Himself."  This is an assumption applied to slaughtering, and a stereotype at worst.  I'm sure that this will bring up the whole trinity discussion, and I really don't want to have that discussion but it deserves a brief mention.

Despite the belief in the trinity, Muslims regard Christianity (and Judaism), put very simply, as a monotheistic religion  —The belief in one God, that is. 

Having said that, eating only thabiha is by far the best and safest option.  That's not the point of this post, however.  Rather, it's about whether it is allowed, or even OK, for us to eat meat from non-Muslims.  And I hope this post arms you with enough information to make that decision.  Another very brief point I wanted to shed some light on is the contents of some of items we eat, whether we think they're halal, thabiha or not.

As listed on Wikipedia, gelatin is:

derived from the collagen inside animals' skin and bones. It is commonly used as a gelling agent in food, pharmaceuticals, photography, and cosmetic manufacturing. Substances containing gelatin or functioning in a similar way are called gelatinous. Gelatin is an irreversibly hydrolyzed form of collagen. Gelatin is classified as a foodstuff, with E number E441. It is in almost every "gummy" confectionery as well as other products such as marshmallows and some low-fat yogurt. Some dietary customs forbid the use of gelatin from animal sources, and medical issues may limit or prevent its consumption by certain people.

You would be surprised to learn that some gelatin is derived from pigs (pork) and is therefore haram for Muslims to consume.  What is not listed, almost consistently, is whether it is from pork or not.  That, technically speaking, makes the item fall into the category of mashbooh; which means doubtful or questionable.  Even more surprising is where and when gelatin is used.  For example, I was shocked to learn that it's in Skittles, which's confirmed to be pork in the US (and supposedly not pork outside of the US —in Europe and the Middle East).  Even more surprising is that gelatin is in Taco Bell's sour cream; although I've not been able to confirm that it's a pork by-product, but is also why I skip the sour cream there now.

The question now, and the reason/drive behind this post, is whether or not KFC's announcement to go halal in the UK is truly halal or not?  Given that their last FAQ question explicitly says that the chicken is stunned means that it's not really halal ... not in my understanding of it any ways.  It must be slaughtered without pain.  Being considered liberal, compared to my thabiha-only brothers & sisters, I still believe that it's not permissible to eat meat from an animal that experienced purposeful pain before its slaughter; not by the People of The Book or Muslims.  It's simply out.

I'm still excited and happy at the direction of the company, but KFC has a long way to go.  See this video for some of KFC's inhumane treatment of their poultry.

Let me know what you think in the comments.