I've built the DTN2 reference implementation from the tip at sourceforge this week, for diablo, if anyone wants me to post some debs. They carry the Bundle Protocol used in DTNs directly over bluetooth and/or TCP/IP. Let me know if anyone wants them.

More info at dtnrg.org and the source is at dtn.sourceforge.net

I've not yet tried DTN-talkie properly, as I've not had anyone else to try it with, but I have got a 7 node DTN up and running, including an N800, an NSLU2 (running Debian), 2 Macs (PowerPC and Intel) and a bunch of other Linux nodes, and a dedicated server in a data-centre, at delaytolerant.net.