Charlie Nesson writes: "Dave, I've started an audioblog, and want to persuade a friend of mine to do likewise. He asks what it takes to listen in a car. Can you help me on this?"
Charlie, that's great news! I totally look forward to listening to your podcast. In the meantime, there are three ways to listen in your car.
1. I use an inexpensive device made by Sony that connects into the cassette player in my car. On one end it's got a cassette, with no moving parts, and on the other, a mini jack that plugs into the MP3 player. Just plug it in and play. The sound is pretty good. They sell them at Target and Best Buy.
2. Another choice is a low-power FM transmitter that connects into the player and broadcasts the signal at a fixed frequency. You then tune your radio to that frequency. The most popular seems to be made by Belkin, they're slightly more expensive than the cassette solution, but are supposed to be more durable, but I've not tried it so I don't know.
3. The most expensive and most elegant (it might require buying a new car!) is to use your car's built-in iPod dock, which functions much like the desktop dock, but get this -- the car's audio controls work on the iPod. This has to be the safest way to listen while driving. However, this is not a standardized interface, and I'd guess Apple has a patent in there somewhere, so you're pretty much locked into Apple if you go this route. But hey -- people don't seem to mind, so go with the flow.
As they say on the Inkernet -- your mileage may vary!