CPM: cost per thousand page impressions.
Casale Media (good for popunders and cmp. hard to get accepted)
Real Cast Media
Value Click Media (Decent Popunder rates, cpm, hard to get accepted)
Burst Media (Great for health and beauty. Decent CPMs, Sometimes get direct advertisers.)
Tribal Fusion (high CPMs but hard to get into, Great pop-under CPMs)
Real Tech Network
Morning Falls Network
Right Media (Direct Media Exchange. High CPM. You can set the CPM you get on other networks and they only fill if they beat the CPM you set.)
Please leave your comments if you know of any good cpm programs that are not listed here.