Been doing some work on optimizing my spamassassin rules to help cut down on the amount of junk mail I get on a day to day basis. Ever since I installed spamassassin and started training the baysien filter on a week to week basis the amount of junk that ends up in my inbox has decreased dramatically.

Here is are a couple of great resources for spamassassin rules:

http://www.rulesemporium.com/ - SARE - Spamassassin Rules Emporium

Spamassassin Wiki - Custom Rule Sets

sa-update - Automatically update SARE Rules

Hopefully you will find these resources useful.