I know popunders and pop-on-click programs are very good but is it possible for a significant proportion of users to avoid pops? And if so can you query(through javascript perhaps) the browser of your visitor to figure that out and then deal with them them accordingly?
of course there are some scripts to detect whether popups are allowed or not. eg http://www.liesong.de/js/scripts/popupblocker_erkennen.html Maybe layer ads are something for you: eg http://www.adpepper.com/DesktopDefault.aspx/tabid-65/90_read-252/