DMA Advertising Mail Suppression
List - This list is used by direct mailers to avoid sending to people
who generally object to receiving junk mail.
Bureau Pre-Approved Credit Suppression Lists - Submit your name
and address to avoid pre-approved credit card offers.
Check out the Computer Professionals For Social Responsibility (CPSR)
To Get Less Junk Mail" (a.k.a. the "Junk Mail FAQ.)