You can find disassembly instructions for the 15" MBP here:
http://www.ifixit.com/Guide/Mac/MacBook-Pro-15-Inch-Core-Duo/85/
Please note, however, that these instructions may not exactly work for the newest model, (Penryn processor, multi-touch trackpad).
Now, it may not be necessary to remove the entire keyboard in order to clean it, but it might be a good idea in any case because you don't know if any liquid got past the keyboard. It might be a good idea to find out, but you will need a lot of patience, some special tools, and a bit of manual dexterity to open up your machine.
If you don't want to risk opening it up, then the next best thing to do is to pop off individual keys. You can do this by gently but firmly lifting up the upper left corner of the key cap until you hear a pop. Then lift up the upper right corner, and you'll be able to pop off the key cap. It's a bit scary at first but once you get the hang of it, it's not so bad. Just be careful not to damage the delicate plastic scissors mechanism--those things are very easy to break, trust me, I know.
You can use a cotton swab dampened slightly with water to wipe off any residue. Then take a 1:1 mix of isopropyl alcohol and water and use that to remove any remaining residue/odor, and go back a third time with distilled water (no mineral content). But I don't know how much mess was made, so maybe just once with regular water is fine.
Finally, go and buy a silicone keyboard cover, like the iSkin:
http://store.apple.com/1-800-MY-APPLE/WebObjects/AppleStore.woa/wa/RSLID?mco=CEE 607B0&fnode=home/shopmac/mac_accessories/micekeyboards&nplm=TK034LL/A
Use it. It's not as pretty as typing directly on the keyboard, but it will protect it from spills, prevent grime from getting underneath, and over the long run, it will also protect the paint on the key caps from being worn off. The key caps on my 4 year old 12" PowerBook G4 are looking rather ugly. I've also pulled out some really gross stuff from underneath--things like hair, dead skin, crumbs. I told myself I wasn't going to let that happen to my new 15" MBP, that I would take much better care of it.
Oh, and friends don't let friends drink and compute.