Allyourbase, if it is of a pornographic nature or Child pornography, then you can inform the Met Police about it. Sadly, they can only do something about it if the email address is UK based.
I have a similar problem at the moment with different mails advertising stocks and share etc....its getting on my nerves, but all i can do is send to junk box and delete.
Alternatively, email programs such as Incredimail have the facility to bounce the mail back to the sender with the hope that they thenget fed up of receiving their own junk mail that they then remove your name from their list.
Also, try not to open any emails that are from people you dont know - not just for the obvious virus reasons, but if you click on a link by mistake, then web address highlights you as a live customer - hence all the following junk mail.
hope it helps
xxxx