paid solution 99% protection and accurate:
http://spamarrest.com/affl?1355307
free solution about 80% accurate and 99% safe.
http://www.spampal.org/
So far I filter about 300 spams a day and have only had 2 emails blocked in the last month with option 2.
I might go option 1 though I have heard it's good..
spam bitches