eMule - eMule is a free peer-to-peer file sharing application for Microsoft Windows.
Acqlite - Acqlite is a Gnutella file-sharing platform based on Cabos, LimeWire and Acquisition.
Soulseek - Soulseek® is a unique ad-free, spyware free, and just plain free file sharing application.
Shareaza - Shareaza is the most luxurious and sophisticated file sharing system you'll find.
Vuze - Vuze is a free BitTorrent client used to transfer files via the BitTorrent protocol.
BitTorrent - BitTorrent is a peer-to-peer program developed by Bram Cohen and BitTorrent, Inc.