If you read all the hoopla surrounding Pandora's upcoming push to become your new car radio, you might get the impression that streaming Internet radio in a moving vehicle can't be done today. In truth, it's been here for a while, and it works great.
I recently tested this idea during a coast to coast road trip from North Carolina to California with a group of friends, where we streamed Pandora through a Blackberry Tour into the vehicle's audio system the entire way. Connected to Verizon's 3G network, we pretty much never lost contact, and only needed to slow down the connection speed a couple of times in the boonies of Texas and New Mexico to maintain a constant stream of tunes that we could control. It worked so well, that the truck's XM radio stayed off the whole time.
Sure, Pandora's new alliances will create systems that integrate more cleanly into the vehicle, but the future is here right now if you want it.