SQL Injection and XSS Attacks

Some topics everyone involved in web development must read at least once:

1. SQL Injection Attacks by Example - It's a lot easier than you think. And yes, you customers will try it out some of the standard approaches out of idle curiosity if nothing else.
2. Real World XSS - You'll be surprised at the sites which are vulnerable to attacks of this nature.
   
3. More XSS
4. And still more XSS