The FTC just issued the Final ruling on telemarketing and prerecorded sales calls. In the new rule you will have to receive permission from the customer in order to deliver prerecorded messages. Consumers however, can receive calls that deliver purely informational prerecorded messages such as you doctors' office that has a prerecorded message to remind you of your appointment.  The ruling is supposed to protect consumers just like ‘The Do Not Call Registry'. The provision that requires prerecorded telemarketing calls to provide an automated interactive opt-out mechanism went in effective on December 1, 2008.

See complete rulings below.

http://www.ftc.gov/opa/2008/08/tsr.shtm

http://www.ftc.gov/opa/2008/12/tsramendments.shtm