Best thing I have ever done for SPAM was to download SpamBully. Didn't even hesitate to purchase before trial ended.
I get about 12k spam a month, but never have to deal with them anymore. There were a few mails I had to train it with, but overall it has been great.
The URL is:
http://www.spambully.com
or if you wanted you could get there through this link
http://hop.clickbank.net/?discount20/spam30
There was another service that sent 'confirmation' emails out to senders to verify it was a real email. But everything had to go through them, so I chose the above. Bully is just a filter, on roids really
Spence