IT Security Forums

thats a very broad question. What kind of security are you talking about? physical security, server security, network, pc, ect.. or you try this link http://tinyurl.com/l9afxa

but Gibson Research used to have, and probably still does, a great security focused forum.

http://www.grc.com/discussions.htm

This website focuses more on malware removal and viruses/spyware etc.

http://www.geekpolice.net

They're really knowledgeable when it comes to removing malicious software.