Just found out about it at http://placebo.hpi.uni-potsdam.de/~alexklim/#docsynch and http://trieloff.dyndns.org/archive/000427.html
It is a JEdit plugin and uses IRC (and DCC - what's this?) to exchange data, so we wouldn't need additional communications tech or service registrations.
I have to run to bread-and-butter work and won't be able to test it soon, but if someone wants to try, keep us posted!
-Bertrand
