ZeroMQ - Distributed Computing Made Simple

 * The socket library that acts as a concurrency framework.
 * Carries messages across inproc, IPC, TCP, and multicast.
 * Connect N-to-N via fanout, pubsub, pipeline, request-reply.
 * Asynch I/O for scalable multicore message-passing apps.

WWW: http://www.zeromq.org/