I was perusing around the website of the Federal Trade Commission brushing up on my rights as an american consumer (I was looking into policy related to telemarketing and cell phones). I noticed that they actually have a database for email spam, they ask you to forward mail to spam@uce.gov. So as you get annoying (and illegal) email messages you can do you part to help fight spam.

http://www.ftc.gov/ftc/contact.shtm