If I ever catch one of these guys I'm going to take a hot poker and shove it in their..... well no need to go further with that thought

Anyway, I've deleted the offending accounts and removed their posts. The following security is already in place
1) people must register before they can post
2) I have one of those "type the letters you see in the box" to avoid bott registration
3) You must click on a registration e-mail to activate the account
I can get more draconian on registration / postings if needed, but not without affecting the ease of normal people to post. I've increased the complexity of step #2 for new users.
We'll see how it goes, if anyone has some suggestions let me know.