Okay, I've set up squid on Arch Linux, using the windows-specific instructions and translating as needed while pulling information from http://wiki.archlinux.org/index.php/Squid
Here's a summary of how it works: it does but it doesn't. It's all set up, but it isn't caching or doing anything as far as I can tell. The following line from the instructions is likely the problem:
Find "TAG: visible_hostname", add a line like "visible_hostname my.domain.net" after the commented lines and replace my.domain.net with your FQDN or likewise
I have no idea what it means by that, so I simply put down "myhost" and later "localhost" for it, and I'm quite sure both are incorrect.
EDIT: Okay, not 100% sure on this, but I think that using the misconfigured squid cache actually made things WORSE, by preventing frequently-requested textures from loading at all!