PDP-11

Ibiblio
PDP-11 freeware archives.
http://www.ibiblio.org/pub/academic/computer-science/history/pdp-11/

Mentec
PDP-11 operating systems plus layered products and services.
http://www.mentec.com/

The PDP-11 FAQ
Information for those who are enthusiasts, curious, or downright confused as to what the -11 was and is, and how it related and still relates to its world.
http://www.village.org/pdp-11/faq.html

PDP11 RT11 Games
Compiled games list for the DEC PDP11 computers running RT11.
http://www.geocities.com/CapeCanaveral/5517/pdp11.htm

The PDP-11 Unix Preservation Society
Devoted to the preservation of all information related to the versions of Unix that ran on Digital PDPs.
http://minnie.tuhs.org/PUPS/index.html

pdp11.co.uk
Information, pictures and profiles on the PDP-11 family of computers and peripherals.
http://www.pdp11.co.uk/

Pdp11.org
Dedicated to preserving the history and legacy of the PDP-11 series of 16-bit minicomputers.
http://www.pdp11.org/

RSTS-11 Library Entries
Compiled by Tim Shoppa.
http://pdp-11.trailing-edge.com/rsts11/

Trailing-edge.com
PDP-11 freeware CDs.
http://www.trailing-edge.com/www/freeware.html

YAPP
"Yet another PDP-11 Page", from John Holden.
http://www.psych.usyd.edu.au/pdp-11/