Ad Zapping With Squid
   A redirector for squid that intercepts advertising (banners, popup windows, flash animations, etc.), page counters and some web bugs (as found).
   http://adzapper.sourceforge.net/

Devshed.com
   Article on tuning Squid on Linux for maximum performance and stability.
   http://www.devshed.com/c/a/Administration/High-Performance-Web-Caching-With-Squid/

Squid for Windows
   Version of Squid written for Windows operating systems. Free download.
   http://www.acmeconsulting.it/pagine/opensource/squid/SquidNT.htm

Squid-cache.org: Hypermail Archive
   All squid mailing list entries from current day back to May 1996.
   http://www.squid-cache.org/mail-archive/squid-users/hypermail.html

Squid: The Definitive Guide
   Advertising site for a book on Squid, written by Duane Wessels. Offers chapter summaries, reviews and purchase locations.
   http://squidbook.org/

Squirm
   A flexible regex based redirector for Squid.
   http://squirm.foote.com.au/

Transparent proxying with squid and pf
   Instructions on how to use OpenBSD packet filter (pf) to redirect http connections to a squid cache transparently without any client configuration. [OpenBSD]
   http://www.benzedrine.cx/transquid.html