Massive spam influx

[#1]

Ok, so I moved over to BBYW yesterday, but since the time I received my email about my new account details, I've received 31 emails from accounts to my catch all address - seems that someone is using my domain name to send spam out to a load of people.
Is there any solution to this apart from forcing all email to other accounts on my domain to a spam inbox?

[#2]

This is a problem called Backscatter
It will subside after a few hours, and there is nothing you can do about it, unfortunately
B.

[#3]

I have a post somewhere detailing how to do as PJ says if you want a step-by-step guide.
Not got time to look around for it right now, but maybe someone else will be along and be kind enough