Notes

[squid-users] squid error for aspx website
[squid-users] Write Error for aspx file
Call Web Services through SQuid proxy server with authentication requested
Unable to access external web sites through Squid proxy server with required authentication.

FindProxyForURL A Proxy Auto-Configuration Resource
Jonathan de Boyne Pollard - Automatic proxy HTTP server configuration in web browsers
Calomel.org - Proxy Auto Config for Firefox (PAC)
Autoconfigure Scripts for Proxy Settings offers some detailed examples
Bust Banner Ads with Proxy Auto Configuration offers PAC file to block assorted (advertisement) domains
King Of The PAC offers PAC files to block assorted (advertisement) domains

EAZ School Proxy Switcher is a freely distributable program that has been designed to make the process of switching between your school proxy network and your home network a veritable breeze.