Check out the free software at mailfiler.com. I haven't used it yet, I came across it when searching for something else last week, I am hoping it will do what it says it will and handle the junk mail.

Not sure how long it's free, but the paperwork says it's only $30 for a single user.

Symantec and others filter all your mail and attaches the words Spam alert to the subject of all potential spam so you can filter it out.

Which will work best depends if you are retriving your mail from a local server or using outlook as a ckient to your isp.