They are going to be called in to righteously kick the shit out of deamons and heretics before fucking off back to Titan for tea and crumpets, leaving the chaos gods thinking "I fucking hate those guys"
The rules are also in the old 4th edition main book (the big hardcover, not the booklet from the starter set)
As far as I know there is no online article with kill team rules on the GW site. If anyone can find them, please post a link. Closest I ever found were the Deathwatch Kill Team rules, which is not at all the same thing.
Upon closer inspection though, these Chapter Approved rules *are* a bit different than the 4th edition ones.
The biggest difference comes in how the teams are constructed.
All kill teams are limited to 160 points and there a number of 'mutable' and 'immutable' laws regarding what units you can and cannot take, etc.
Immutable laws cannot be broken (except in special one-off games), mutable laws can be, but give the other player bonus points to upgrade their goons or bosses.
So while the rules above will let you play a type of kill team game (a bit simplified version) it's not the same as the current (4th edition) rules. If you make a kill team witht hose rules you should tag it as such, like 'Tau Kill Team (CA)' int he title so people know you;re not using the 4th edition KT rules.
Unfortunately, unless someone can dig up a link from games Workshop, we can't give you the full rules, but if you can find an old 4th edition copy of the main book (they;re bound to be cheap with the new edition out) you can find it in there. Get the hardback thoguh, it;s not in the boxed set booklet
That sucks. But I believe my friend might have an old copy. See, I'd like to play a Kill Team Game. Play a lot actually, considering all my Marines have been customized with their own looks and each have their own names. Haha.