I got my hands on XtremeMac's latest in-car iPhone power adapter, the InCharge Auto. As luck would have it, CNET car tech writer Kevin Massy loaned me his trusty desktop car lighter power supply to see if the adapter was worth its salt.
The result? It works! In fact, the adapter's standard USB connection will likely work on other USB-chargeable products as well.
For just $20, this seems like a good solution for charging you iPhone between destinations.