Nicotine Plus is a Python port of Soulseek, the popular P2P file sharing app. (It replaces the SoulseeX project, which is no longer supported).

They need some help getting it working on OS X. See Nicotine+ and Nicotine-Plus: PyGTK2 Soulseek Client | Get Nicotine-Plus: PyGTK2 Soulseek Client at SourceForge.net.

(I'm not affiliated with Nicotine Plus. I'm just a user who would like to see that project working on OS X.)