There are methods to stop actual spam bots. You would have to find the 'member' who registered. To prevent a bot from registering, some forums have you enter a randomly generated set of characters. This deters most bots from registering but AZ does not have it in it's registration. More alarmingly, at this point, the spam is forwarding itself automatically. I have no instance of sending out this 'Check this website' PM in my sent folder. Yet, two members already said I sent them something, including a PM, calling me a loser. That's fine since this is a misunderstanding. However, finding the original bot/PM will have to be done by the admins. So good luck to them. In the mean time, if you do receive SPAM, please don't go off assuming that the sender is a jackass.
*Posting a list of all names you received the spam from may help admins so making this a Sticky and have the OP's post updated with the names of all senders you receive the spam from*
benCho-