IIRC, vegan seems to be more extreme form of a vegetarian. They have to eat off special plates, and have lots of special rules that they follow. (this off the top of my head)

Vegetarians just don't eat meat or animals.

However, as an interesting sidenote, I do have an friend that is a vegetarian, but about twice a year he gets a hankerin' for one of 2 things. One is prime rib (medium rare) and the other is a big plate of bacon and eggs. <img src="/images/graemlins/grin.gif" alt="" />