PDA PROS has a great suction cup type car holder for the TREO 300. I got two on for each car along with the universal car "fone" kit from heartlandamerica and have a terrific hands free set up. for a very small ammount. The PDA PROS unit is adjustable in every direction, making it a snap to set up in any car.

PDAPROS got it to me in no time flat!

it also has the advantage of being able to be easily moved from car to car.

in fact i intend to take the car holder and car "fone" set up when i use a rental car on vacations.

The set up for both cars, from PDA PROS and heartland direct cost less than $65 per car!

also see my thread on the universal car "fone" kit.