Just out of curiosity, why not use Youtube to serve the video? It's free and comes packed with loads of brand promotion built right into it.
Vimeo is an alternative if you want something more professional (you can get a customized player if you pay for it).
Alternatively, you may want to checkout a Content Delivery Network (CDN). I had a client who broadcast video using Limelight (
http://www.limelight.com/) and it worked pretty well for them. Proved much cheaper then trying to feed that bandwidth through a traditional web host.