I would like to make some money with my 10,000+
page-views/day message board. 90% U.S. traffic.
Music-related message board. I would like to try
pop-unders or exit-page ads.

I tried netrift.com and webhitsdirect.com but they rejected
my site (reason: message boards are not accepted)

I want to be paid by paypal.com

Thanks

u can try focalex.

also now advertwizards have started popunders.

then thereis paypopup - exit exchange.

I'm not sure if these allow forums, but you could try:

http://www.popuptraffic.com/

http://www.exitfuel.com/

http://www.goclick.com/affiliate.shtml

http://www.popupsponsor.com