This isn't actually a tutorial, so I apologize if you were looking for such. However, this is something that anyone interested in hacking, security, law enforcement, law science, etc., should read.

Put your feet up, because it's long.... but it's something every techie on this side of the fence should know.

The National Information Infrastructure Protection Act of 1996

Also, if you search for the word "breaking" on the page, the first occurance contains information about lawfully "breaking into a computer system." This is where a lot of rumors can be hashed out, because it's not as black-and-white as some will lead you to believe.

Remember, information is the best weapon to arm yourself with.