SolarSeek is an Open Source version of the SoulSeek client for OS X.
Its development has ceased long time ago and the home page reflects this.
However I assume there are people that still use it, even though it's old. But all it really needs to do is find files that other people share and have you download them. The social tools they were incorporating before the development stopped aren't really "core" functionality.
So, as of Mac OS X 10.6 SoulSeek crashes at startup. Some EXC_BAD_ACCESS failure... whatever, no-one cares, it does not work. I downloaded the source code which is still available at the google code project page and compiled the latest (and last) release 0.95.3 for Snow Leopard. I didn't do any quality control. All I noticed is that it works for me.
If the project owner would be so kind to do the same and put up a new version online then SolarSeek wouldn't be completely dead.
For those of you who want it, here it is: SolarSeek 0.95.3