If you want to consider an in-house solution, then I would look at either TotalMD, Lytec, or MediSoft. Those seem to be the ones with the least amount of hate-to-love ratio.

If you wish to out-source your billing, then I would like to, of course, recommend my own company. You can see our website address and so forth below.

JamesNT

James Summerlin
My personal site: http://www.dataintegrationsolutions.net
james@dataintegrationsolutions.net