Another thing is to use livestream.com. I was just poking around and noticed they have their own
production switchers they sell. I've used their
procaster as well (free software based simple switcher) that works pretty well.
Although there are pros & cons to both, I think
Livestream ends up being a bit better than ustream in that they offer procaster, ad-free viewing, and HD streaming with their free plan.
Basically until you start investing lots of $$, you can't do multi-camera views (unless you pull it directly from the feed that they use for the big screen)