A couple of months ago I wrote a little application for Regulus Labs. The application is a simple daemon bridge between Sangoma E1 devices receving ISDN PRI calls and a TCP IP server. Everything received on the telephony side was simply bridged to the configured TCP IP server. The bridge supports PRI voice calls and V.110 data calls.
Even when the application is simple in nature, learning about V.110 to get it to work was interesting 
Today I made the project public ( thanks to Tzury Bar Yochay from Regulus Labs) in google code:
http://code.google.com/p/sbridge/
Hopefully somebody else will find it useful.