http://en.wikipedia.org/wiki/National_Do_Not_Call_Registry
Does not require private information ( no credit card, address or even name), but it does require 5 minutes to complete the process by waiting for an eMail and then clicking on the link inside that eMail.
Also, after moving and terminating the old number, the registration remains for the old number, and there is apparently no method or obligation to un-register.
