Livestation has been available for some time for Windows and only recently for Mac. Livestation uses a Silverlight front-end to playback broadcast streams, encoded in VC-1 format, received over a peer-to-peeroverlay network. The program from London based company called Skinkers is an attempt to get in on what Joost and others started before them. You can watch TV broadcasts from Discovery Channel, Nickelodeon, Fox, CNN, well you get the idea. The stream is very high quality and seems to as of this writing, get very bogged down and time out a lot. This may be due to the recent Mac release or it could be that it is just that good, which I think must be the case. The program is worth getting and using if you watch content on your Windows, or Mac computer. Sorry Linux users, no Livestation for you.
Update: See the comments below, Linux version coming soon.