I have not done this, but it seems like it would work.
You will need two to buy 4 seperate products.
1. Fortuna U2 PS2 GPS Reciver
2. Fortuna Treo 600 Adapter cable
3. USB Battery Pack
4. Mapopolis Software
The Fortuna Treo 600 Adapter cable has a USB port to provide a power source for the reciever. They offer a USB to Cigarette lighter adapter, however you can just get the USB Battery Pack instead. It may not be real slick, but it should work.
Here are some links
http://www.fortuna.com.tw/u2.htm http://www.expansys.ae/product.asp?code=108897 http://www.expansys.ae/product.asp?code=112534 http://www.isellsurplus.com/product....17&ID=7936&P=F http://www.mapopolis.com/products.js...7267975&p=&q=2