Over the last few months a number of people have complained about receiving spam PMs, or Private Messages that were offensive or innapropriate.
If you don't want to receive any PMs from an individual you can add them to your "ignore list" which you'll find in your user control panel
-- this will also hide all their posts when you're reading the forums (which may or may not be a good thing!)
If you want to report a PM in the same way that you can report a bad post, you can forward it to me with a note explaining why you are unhappy with it and I'll take any action that I feel is necessary.
I hope that this isn't something that will need to happen often!