Attrition's Newbie Area
Newbie-oriented tutorials about stuff like UNIX and system penetration auditing.
Hacker Smiling
Contains books, tutorials, downloads and links to other sites.
Hackers World Portal
Links to hacking history, cryptology, censorship, international hacking groups, news, publications, security, weekly features.
Hackerthreads.org
Tutorials about networking, system administration and network utilities.
How to Become a Hacker
A short essay on becoming an "old-guard" hacker (NOT a cracker or phreaker).
How to become a Hacker
ESR's paper on how to become a Hacker.
Linux Documentation Project
Compilation of tutorials and HOWTOs for the linux operating system.
The Happy Hacker
Home of the Guides to (Mostly) Harmless Hacking. Focus is mainly on Windows 95 and 98. Some mention of Windows NT.
The New Hacker's Dictionary
Hacking jargon including information on writing style, hacker terms, and lamer-speak.
^Rob's WerLD
Contains information about viruses and trojans and their fixes. For newbies and advanced.