This has been on my TODO list for at least the last six months or so: Growing the experimental GPRS branch of OpenBSC into something more useful.
Right now, you can use OpenBSC with a GPRS-capable BTS - but only if you have an existing SGSN to serve the Gb interface of the BTS. This somehow defeats the point. We want to offer a 'GSM network in a box' solution, where no other non-free Software is required to run a fully functional small network.
So right now I'm cleaning up the 08.16 (Network Services) Implementation, and will move my way up through the existing 08.18 (BSSGP) and LLC code that I wrote some time ago.
With some luck, in a couple of weeks we should be able to run a self-sufficient combined GSM + GPRS (+ EDGE) network out of OpenBSC.