Reference:

Printable ASCII Chart (pdf)
Color-coded ASCII Reference
Extended ASCII Character Reference
vi/vim Quick Reference (pdf)
Internet FAQ Archives
bash (shell) Reference Manual
Unix Help for Users

Tutorials:

Mastering the vi editor
Learning Linux Online
Learning GNU C
Learning Perl

Security Sites:

Secunia
SANS
CERT
dShield

Research Sites:

AT&T Research Labs
Bell Labs
Palo Alto Research Center
CSAIL (MIT)
Microsoft Research
Stanford AI Lab

Organizations:

Association for Computing Machinery
IEEE
ISO
W3C

Notable People:

Hal Abelson
Alfred V. Aho
Gordon Bell
Tim Berners-Lee
Fred P. Brooks
Peter J. Denning
Brian W. Kernighan
Bruce Schneier
Eugene H. Spafford
Bjarne Stroustrup
Linus Torvalds
Larry Wall

Miscellaneous:

Computer History Museum
Modern History of Computing