Is the mailing CAN-SPAM compliant?
If so, see sig.
Also, join <a href=http://www.epiccash.com/WR_track/WR_track.php?UID=ngndcom>Epic Cash</a> and contact p1mpdogg on ICQ. He'll probably let you include a remote join box directly in your email. His database is only about a month old, so there's a lot of oppurtunity with the program.
If it's CAN-SPAM compliant and double opt-in, check out <a href=http://www.wegcash.com/?wm=ngnd>WEGCash</a>.