VoIP for Deployed Soldiers?

rickbassham asks: "With VoIP really catching on these days, I decided to look into it for keeping deployed soldiers in touch with family and friends. I am currently a soldier in Iraq, and have the ability to get satellite-based internet, thanks to a few of the locals. While individually it is prohibitively expensive, a group of soldiers can come together to purchase a decent-to-high-speed internet connection. One of my plans is to link other soldiers to Vonage or another VoIP provider, so they will be able to keep in touch. Understanding the latency issues with VoIP via satellite (not to mention the other disadvantages), what upload speed does Slashdot recommend as a minimum for a QoS enabled connection for about 15-20 soldiers? The same for a non-QoS connection? What recommendations do you have for a good VoIP provider?"