1) 9.99 a month extra line. This is a 2nd cell phone # that becomes the Veh's new Tel. #. This charge is for the 2nd line and is added to your monthly plan charge.

2) Need to have one of the Verizon Family Share plans, to be eligable. For example, the 1400 minute anytime minute plan.

3) It is strictly a handsfree calling device. No voice mail or enhanced services. If you are in the car with the ignition on, calls can be made or rec'd. If the ignition is off, the phone will ring for the caller about three times and then just falls off. There is no ringing in the veh. unless the ignition is on.

4) The Onstar Device tel. # uses its minutes from your bank of monthly allowance minutes during peak calling.
All other promotions for minute usage still apply. For example unlimited Verizon Wireless calls, Unlimited Nights & Weekends.

Everything else is the same as with the Handset, asfar as the plan goes. You just don't have the voicemail and enhanced services. It works really well.

The new Cell phones are Digital only for the most part now, to be compliant with the FCC. Starting with Model year 2008, the Onstar devices will also follow suit.

Right now they are still Tri-Band, Digital/Analog. Analog, by its very nature carries further and with Onstar, gets a better signal in rural areas. I've been in VT, with no cell service but can make and receive calls with the Onstar Device no problem. That will all change in '08. Unless of course the Companies put up a lot more Cell antennas.
It's like FM and AM. Now ther's XM. What will be next for Cell phones?