Check out how your isp handles newsgroups. If they do it well you'll get lots of music at maximum speed. Also if Soulseek hogs memory even after it's closed use a program like FreeRam XP to reclaim some.
http://www.yourwaresolutions.com/
http://www.newzbin.com/browse/cat/p/music/
http://www.nfonews.com/Cat.asp?c_id=11