Acceleport RAS 4 and VOIP/PBX

I got lucky and picked up an hp ml370 server with a ras4 card installed in it for next to nothing on ebay.I have decided to put linux/dapper drake/server edition on it.I would like to hear from anyone who has implemented voip/pbx with this card.I believe since it is basically a 4fxo card there should be software around to make it process incoming analogue calls efficiently and send it across the internet using standard protocols.Any ideas would be welcome.