This is a bit involved, so I’ll post a link to my blog when I get around to blogging about it. ;)
www.manageengine.com/SecurityManager Scan for Open Ports and Network Vulnerabilities. Free Download.
www.infosecinstitute.com/ Hands on ethical hacking training learn to write exploits
www.ask.com/Security+Vulnerabilities Explore Security Vulnerabilities. Get Answers Now on Ask.com.