Welcome to WebmasterWorld Guest from 220.127.116.11
Also the ones who would hack your site read these boards too, 'nuff said about that . . .
There is, however, tons of info here. In respect to coding up your applications, try some G searches in the format [keywords] site:webmasterworld.com. Here's a couple:
mysql injection [google.com]
XSS [google.com] (also try Cross Site Scripting)
site security [google.com]
You'll get lost for hours . . . tons of info here. :-)
If there is one bit of advice that goes largely ignored, it is this: every user input is a potential hack. - Selena Sol Learn to filter your input, throw away everything you don't want, and it's a good start.