I'm surprised that ZipCar (
www.zipcar.com) didn't get in there first, but I guess right now they are just in the much bigger cities. They have been in D.C. for quite a while now. Many areas actually have designated parking spots for the zipcars (this is for the unused car to be parked, not for a zipcar to park in when they take it to the grocery store for example) so that they are easily accessible by everyone.
Obviously the program is just starting in Utah and thus is going to be quite limited for at least a while, but to become more successful I would imagine that they are going to have to have zipcars available in areas that may not be next door to a mass transit station but are in a densely populated area...sugarhouse might be a good option. It would also be wise of them to start the program with cars at BYU since that campus is must more of a people living close by without necessarily have cars.
Finally, I hope the program does work in Utah, but it is easier in areas when you only occassionally need a car--maybe once a week or so; start getting much higher than that and the economics start going down a bit (and yes i realize it includes gas and insurance).