IETF - http://www.ietf.org/
NIST – http://csrc.nist.gov/publications/PubsSPs.html
SANS – http://www.sans.org/
ISECOM – http://www.isecom.org/
OWASP – http://www.owasp.org/index.php/Main_Page
Bruce Schneier - http://www.schneier.com/index.html
Remote Exploit – http://www.remote-exploit.org/
Wireless Defence – http://www.wirelessdefence.org/
Bouncy Castle – http://www.bouncycastle.org/
Insecure.org – http://insecure.org
Secunia – http://secunia.com
RobText – http://www.robtex.com