“No reason to be a cable jockey and contstantly switch the 12V charger in the car between the GPS and the phone/PDA with the solar powered HBTGPSOL Bluetooth GPS receiver:

The solar cells can charge the device when it is off and they increase the normal operating time by 50% to an incredible 30 hours if the GPS is on the whole time.
The HBTGPSOL comes with:
GPS antenna
Quick Start Guide (English and Italian)
Cd-rom with utility and manual
USB cable
AC-DC power adapter (5V-500mA)
12V DC car charger
Li-Ion rechargeable battery”….