Michael has released SpamSieve 1.3, which is more resilient than ever to spammers' tricks for obfuscating words. In addition, you can now use e-mail addresses in the system Address Book as a whitelist, so that messages sent from those addresses will never be marked as spam. Michael continues to optimize the app, greatly reducing the overall memory usage as well as launch and quit times. A complete list of changes can be found at the above link. SpamSieve requires Mac OS X 10.1 or later, and supports Emailer, Entourage, Eudora 5.2, PowerMail, and my personal favorite, Mailsmith. It's only $20, it's shareware so you can try before you buy, and it nips my spam problem in the bud. Give it a whirl, and support a shareware developer.