Hey I got me a holder from a site called gps for less (I'm in the UK btw), the holders great at attaching to the windsheild and also comes with a stickey base so you can attach it to other parts of the car as well (the sucker still works so you can remove the holder leaving behind the sticky base)... it comes with a 12v car charger and an RJ11 connection for connecting to your GPS unit... best of all it only cost me £35 (approx. $50??).
Have a look... I'm well pleased with mine...
http://www.gpsforless.co.uk/product_details.php?id=1148
If you're in the UK, gpsforless = brilliant service! Super fast delivery even when I changed the deliery address at the last moment!!