Here is a list of animal derived ingredients. I know it's overwhelming, and at the bottom is a link to see ingredients that MAY come from animals, but there are some tips at the bottom to help you sort through it all and live a more cruelty free lifestyle.
The following ingredients are derived from animals:
Basically, as far as food is concerned, look out for lecithen, and ingredients that begin with the prefix "stear," as these are the most common and may be animal derived. Use common sense, if you don't eat honey then don't buy something made of beeswax. Lactose and whey come from milk. So just read the labels and be cautious. Print the list out if you want and take it with you, or learn the more common ones and stay on your toes. Stay strong, never give up.
This list is From the National Anti-Vivisection Society's "Personal Care with Principle," Spring, 1992. I believe that it has been updated since that time. Click here to go to the list of ingredients that MAY be derived form animals.