SourceForge.net. Fast, secure and free downloads from the largest Open Source applications and software directory

Possibly the most detailed CVE security vulnerability source on the internet. You can search for software and hardware vendors, products and exact v...

PHPCrossRef - PHP Cross Reference Library

The Exploit Database - Exploits, Shellcode, Vulnerability reports, 0days, remote exploits, local exploits, security articles, tutorials and more.

Security mailing list archive for the Nmap lists, Bugtraq, Full Disclosure, Security Basics, Pen-test, and dozens more. Search capabilities and RSS fe...

Twitter is without a doubt the best way to share and discover what is happening right now.

SecurityFocus is designed to facilitate discussion on computer security related topics, create computer security awareness, and to provide the Interne...

Ohloh is an open source directory that anyone can edit. It features comprehensive metrics and analysis on thousands of open source projects.