We just got a couple of servers up and running and were hoping to use BILLADMIN, however, Matt seems to have stopped taking orders. Can anyone give us some references to billing solutions that are similar to BillAdmin. Thanks:D

www.billmax.com
www.revecom.com (has some billing management features)

I'm sure there are others, but I can't think of them right now :D

Take a look at CBMS; it's free.
http://www.voxel.net -> software -> cbms

Check out the new screenshot, this is a preview of the commercial version.