The Ricochet Robot Game Server implements the Ricochet Robot Game Protocol to permit multiple users to share a Ricochet Robot game. The server can be found in CVS in the the rrserver module.
While the protocol is usable through an ASCII telnet interface, it is much easier to play with a graphical client. Two such are available in CVS, in the RRClient and grrobot modules.
Work is also nearly done in the RRbot module which holds an IDA* solution searching application.
Instructions for accessing these modules can be found in the keithp.com CVS instructions.
Feel free to use the rr game server on port 5252 (the default for most of these applications) on rr.nickle.org.
Discussion of the protocol as well as client/server software takes place on the RR mailing list.