Bram Cohen, BitTorrent founder recently applied for a patent on shiny new peer to peer streaming service called “BitTorrent live”. BitTorrent live is born after many years of experimentation on how to stream live video without unnoticeable delay for the viewers. I assume that you know how BitTorrent protocol work. On BitTorrent everyone who downloads a file becomes a peer and uploads the file to other peers. And there should be at least one seeder to make it work.
BitTorrent Live works the same way. Here broadcaster is the seeder and viewers become peers. So this means your upload bandwidth gets utilized to stream to others. This will look like easy at first glance but live streaming is very different from BitTorrent file downloading. Its because everything needs to happen without a break and if there is noticeable time interval between the live broadcast and viewers, it cant be called a live stream at all. All the data packets which you receive from other peers need to be assembled seamlessly for uninterrupted viewing. This is why developing such protocol took long time and finally its ready for the prime time.
You can try out BitTorrent live service here . You will need to download a small client application which does the P2P sharing and its available for Linux,Windows and Mac at the given link.