I noticed in the match fred that some people (C-Diddy) have issues with iSky. Since PMs have gone, I'll just post here.
I used to have issues with iSky, in that it tried to buffer every few seconds. I think I could get to maybe 2 minutes max before it gave up and buffered again.
This helped a lot: http://www.geekzone.co.nz/forums.asp?topicid=101428 . Basically you edit your hosts file (STFW if you don't know how to, there should be good resources out there) and tell your computer to point directly at iSky rather than doing DNS crud that slows it down.