What are some alternatives?
When comparing Soulseek and MLDonkey, you can also consider the following products
eMule - eMule is a free peer-to-peer file sharing application for Microsoft Windows.
Shareaza - Shareaza is the most luxurious and sophisticated file sharing system you'll find.
aMule - aMule - the all-platform P2P client!
Fopnu - Fopnu is P2P File Sharing System. 100% Free, Simple and Easy to Use. Contains NO Spyware and NO Ads.
BitTorrent - BitTorrent is a peer-to-peer program developed by Bram Cohen and BitTorrent, Inc.
RetroShare - RetroShare is a open source cross-platform, private and secure decentralized communication system.