Several layers of complexity there, BRL.
At the simplest level the mobile phone is seen as a modem by the PC. Not much different to the modem in the PC already except the the phone then does extra processing & handles the connection to the mobile phone service instead of a normal modem's connection via the phone line. You'll need driver software so that your PC can use the mobile's modem device
The connection will be at whatever data rate your mobile service supports. Standard GSM is slower than a normal V90 modem. (9.6 Kbps vs 56 Kbps for V90). Some mobile providers & phones support enhanced GSM data rates that bump the data rate up a bit to 14.4 Kbps. Others offer even higher speeds (for a cost) eg High Speed Circuit Switched Data (HSCSD) at up to 64 Kbps and General Packet Radio Service which is 'always on' & maxes out at as much as 170 Kbps. Even faster is 3G which is starting to appear but isn't very common yet. The US seems to be opting for 'EDGE' which is yet another enhanced data communication protocol.
The connection to the phone can be via cable - somewhat like a standard external modem - or via infrared or bluetooth. The driver software for the phone's modem function + the driver software for the bluetooth on the PC should allow the PC to see the phone as a modem device connected via bluetooth.
Last edited by Tinstaafl; 19th January 2005 at 01:58.