My hubs sent this link to me today and it looks to be a mighty handy one. SpamGourmet

Basically, you give them your real email address that acts as your forwarding address, and they create endless false email addresses for you to use in signing up at various online newsletters, services, stores etc. All the businesses will see is an email that works, they'll never see your real address. THEN, when you receive spam from anyone, you can track it from the temporary false email addressed it was supposed to be sent to. Thereby discovering that JCREW.com sold your email to a third party. Handy huh?