This site is really the best one to learn the basics of hacking, it has challenges and its all legal... www.hellboundhackers.org and www.hackthissite.org but hellboundhackers is the best one for that. I am registered there and here at go4expert.com, trust me, that site will learn you alot that you never knew... "I will rather die standing than to live on my knees." - Grindordie.

Astalavista!