Typically, a satellite dish can be mounted in the roof of your RV. It is connected to the satellite modem, which is in turn connected via a USB or FireWire port, to your PC. Basically, all you need to make it work is a single USB port for the satellite modem, the appropriate power connections (no big deal on today's SUVs that can probably provide power to all of Iraq, if necessary), and a satellite dish from one of many providers.
One source for such systems is Ground Control, located in San Luis Obispo, Calif. This company offers a complete mobile satellite system, called Data Storm, which can be used for mobile Internet access, voice over IP connections, and can even receive DirecTV broadcast signals. Service is based on a flat monthly rate, and you can receive signals and send and receive data even as you are rolling down the long and winding highway. Of course, we still suggest you pull over to get the full (and safe) wireless Internet experience.