GSM Phone modem

Has anyone used a Motorola GSM quad phone to work as a phone modem for
a laptop?

Looking for a quad phone to use here in the US with Tmobile or Cingular
and for overseas travel. Features that would be nice are SMS,
calendar, appointments etc. I think the V400 may work, but not sure
about modem capability. Mainly want to know about connecting my laptop
for occasional internet service and data downloads from instruments in
the field.

What phone would you reccomend?

Thanks

JerryB