Stupid question...

[hiimcliff]

Can you have voice service with one carrier and just internet (gprs, edge, 3g) with another carrier? is this possible?

[levenum]

Theoretically, yes, but you would need:
a) A dual SIM adapter for your phone and you would have to switch between SIMs (which in some cases involves reset)

b) The carrier would have to agree to sell you a "data only" package. Such packages are usually offered when you by a cellular modem.

[N2h]

another option could be having a 2nd phone with bluetooth, having a sim in that device with just a data plan.
Your PDA connects to the 2nd device via bluetooth- DUN - (or internet sharing in WN6)
so when your making calls the you use 1 sim and to connect to the internet you use another device,
I use to use this method a few years back, when I had work sims, with unlimited data plans, -
the spare phone use to just sit in a bag or pocket and never had to be taken out-

on a slightly off-note,
i came across a review eith on engadget or another site a year ago, where they had this PDA that could take 2 sims at the same time and work on 2 networks at the same time, im sure it was a south Koreans or tiawnes model,