Open source program for Windows which has its own network derived from Gnutella and which is also able to handle BitTorrent and Shoutcast.

Decentralized file sharing system for MP3 files featuring resumable and distributed downloading.

Offers Mac software that allows you to share files, search for files, resume stopped downloads, and create own chat rooms.

File-sharing program for the Mac featuring multiple servers and unlimited results.

File sharing tool with public key encryption, instant messages, chat, free e-mail, message boards and file collection organizer.

Network for sharing legally traded live music in MP3 and SHN formats.

Music sharing, playback, and recommendation program for Creative Commons licensed songs. Gnomoradio is free, open source software for Linux/UNIX systems.

Free (GPL) peer-to-peer framework of the GNU project with a focus on anonymous file-sharing. Works under Linux, BSD, OS X and Windows.

Open source peer 2 mail application for Windows and GNU/Linux that lets users share, store and manage their files via e-mail accounts.

Software and protocol enabling secure distributed communication and file sharing for small trusted groups of users.