P2P is well known in the music comunity, but there is much more than that. P2P opens new ways to businesses, too.
Sun Microsystems has a nice review of this, here: Beyond file sharing.
It presents the JXTA project and shows the real business benefits of peer-to-peer technology. Project JXTA is a set of open, generalized peer-to-peer protocols, offering great advantages to its users.