suggestions needed: free email spam / filter program or service

I'm looking for a free (or damn cheap) email filter service or program for one of my blogger friends. She's getting a ton of harassing, insulting emails and wants something that will filter out insults & hate speech.

I've seen the different authentication services that some folks use when I contact them for the first time, but I don't know if they help in this sort of situation.

What she's looking for is something that would ideally park those things into a bucket or delete them outright. She would be comfortable with losing emails that are mistakenly lumped in there. Any friendly that gets their message hosed would be instructed to alter the language or submit written content in a .pdf or something.

Any ideas?

-arvan

SexGenderBody.com
@sexgenderbody (twitter)