This one is a rather maximalist one : "The New Hackers Dictionary" aka "Jargon file": http://jargon.watson-net.com. It is not only an excellent resource, but also highly entertaining reading. Recommended.
To add entertainment to entertainment, here is another link I like: "A Guy's Guide to Geek Girls": http://cs.wheatonma.edu/pathways/humor/GuideToGeekGirls.html
A rather complete list of computer-related abbreviations and acronyms is found at http://www.geocities.com/ikind_babel/babel/babel.html[an error occurred while processing this directive]