I'm looking for some software for a high school TV news broadcast. All the hardware is in place, with cameras interfacing with a computer (running XP) and the broadcast output being fed to a second screen. I just need some software to put it all together. Currently, we're using Adobe Visual Communicator 3, but this software requires you to use a pre-configured timeline. If anyone slips up and talks for too long (this is quite likely), then the software cuts to the next scene, no questions asked. I need something that's cue-based and has greenscreen capabilites.
What alternatives do I have?