Learning to Hacking knowledge

Anybody has good tutorials for learning to hack?i want to learn hacking to expand my networking knowledge.I will not use hacking for illegal.if anyone has good forums ,tutorials and websites upload here.

I see you often have network related queries, but why not spend a few days on a networking course (if your employer will fund it).
It would be the quickest way, since you will have the knowledge within one week.
Personally I would advise a networking-related course, and probably a computing-related one too, e.g. Linux admin course, even if you
are not interested in being an admin; it will teach you about data and protocols that traverse networks.
Alternatively, there are a lot of resources on routers and switches, and it is relatively easy to experiment with a couple of PCs and some
old switches and routers. You are also lucky that 99.99% of network "features" are all publicly accessible documents, known as RFCs, which are
free to read and study from.

can be used for hacking...

sample cases for how to Hack a WebSite Using BackTrack 5
https://www.youtube.com/watch?v=StFZj3J-ooM

hello friend,
if i go for networking classes also i put doubt in user forums.if u go classes u cant get all.if u want help me,give me good websites and ebooks related web sites.