Below are the tools that will help you to teach yourself to stop hackers:
- The Web Application Hacker's Handbook (her bible)
- Head First SQL (another favorite book)
- WebGoat, which is a site and free software that teaches web hacking.
- XSS Challenge, a contest that teaches hacking.
- Various "Capture the Flag"competitions, a popular way to learn about security,like this one put on by NYU.