Shareaza 2.1

Shareaza is a file sharing system that can harness the power of up to four separate peer-to-peer (P2P) networks, including EDonkey2000, Gnutella, BitTorrent and Shareaza's native network, Gnutella2 (G2).

Not only that, but Shareaza is completely FREE and won't show any annoying ads or pop-ups. It won't install any unwanted third party programs that can wreak havoc with your computer. No spyware, no registration, no "paid version". Just download and use. Simple.