It could be your isp provider yes. Some apply filters to slow down p2p sharing b/c it uses so much bandwidth. I think isp's that do that are sneaky since they are limiting your services without your knowledge or approval.
You could try downlding a magnet link from here to see if you get good speeds:
http://www.magnetmix.com/video.shtml & to see an example of what speeds you can get see Stief's example here:
http://www.gnutellaforums.com/showth...692#post138692