Xeerkat is a free, open-source and cross-platform P2P computing framework that uses the XMPP protocol for communication.
Xeerkat employs a basic agent computing model that runs a number of services (available over both HTTP and XMPP) available to peers.
Being developed using Java, Xeerkat is a cross-platform framework which can be used on any operating system that comes with Java support (e.g. Mac OS X, Windows, Linux).
Detailed instructions on how to install and use the Xeerkat utility on your Mac are available HERE.