The best resource for that is Wallsrx, they have an excellent database that is very up to date, you can just do a search under the imprint on the pill to find out what it is, here's the link:
http://www.wallsrx.com/services/cpident.cfm
If you have problems finding the ID yourself, you can also post it here in the Drug ID forum and some of us will gladly look it up for you.
verwon@gmail.com
My information is not guaranteed correct. I do not get them right all the time, but I do enjoy the hunt~