JXTA pronounced "JUXTA", is a P2P protocol designed to standardize P2P
communication,and it's open source.
i have quite a good knowledge about the protocol as i made few projects in
addition to my college graduation project with JXTA.
u can find more info on "www.jxta.org", and u can message me on my email if u
needed anything or more info.

The power of JXTA is that it gives you a fully fledge protocol for
creating P2P stuff, the weakness is that it can take a /very/ long time
to learn  how to harness that power.

However the good news is if you search over the jxta.org website you
should find a build that is designed as an entery level version, which
does a lot of the stuff for you and it is pretty powerfull for most
applications and a good way to bend your brain into jxta.