Thanks for the input.
The satellite dish ended up being off limits, so whether we used the high school or middle school became a moot question.
Since we're watching the webcast, we're just going to run it full screen on a laptop and connect that directly to the LCD projector. We're also going to run two feeds concurrently (broadcast.com and NASA), so if one starts buffering, we can still watch the other one.
Hehe, can't wait!!