Yes, OSP has been slow in taking off but is definitely gaining momentum. Some of the big carriers - MCI, Primus Telecommunications, NTT etc - are already using OSP to manage their networks. The protocol is fairly mature & stable now (in version 1.4 I think) and provides a lot of flexibility; you can convey presence information, capabilities information (channles, bandwidth etc), and even pricing information for each destination. I beleive that over time it will evolve as the preferred
method of inter-connection for IP based communications.