Amazon S3 has BitTorrent support and it`s amazingly easy to setup.
For those of you already adept with S3, setting up a torrent is amazingly easy.
Make sure your file is publicly viewable within your bucket and proceed to access the file in a web browser as you usually would, but add ?torrent to the end of the URL.
Amazon creates a torrent file and it automatically comes up as a download in your browser. Now you can publish the .torrent file online or hand out to your friends to distribute. Amazon takes care of the tracking and boosts the initially seeding. However, after the swarm speed is moderately speedy, you will want to delete or take away world readable permissions of the original file if you are worried about bandwidth charges from too much S3 seeding. This tactic might come in handy if your torrent file somehow ends up on digg and you don’t want to be handed a large S3 bill.