The Internet Dictionary

NetLingo "has thousands of definitions that easily explain the Internet and the online world of business, technology, and communication."

In additon to the dictionary, the site also provides the top 20 internet acronyms every parent needs to know, top 20 tech terms that are now common expressions, and top 20 newbie terms eveyone needs to know.

There's also a handy list of acronyms and text messaging shorthand, plus a list of online jargon and a list of smileys and emoticons.