Good Uses For Modem Teaming?

legana asks: "We are just about to install multiple cable modems at our office and we were wondering how to make the best use of them. What software/hardware is available that will allow us to share the modems across the network but still allow certain users priority (for uses such as video-conferencing, etc.)? Is it better to share all the modems across the entire network or break the network into subnets each with their own group of modems? Does connecting multiple modems to one computer really increase the bandwidth available?"