Using a phone as a gprs modem

i installed ubuntu 9.04 its working well.unfortunately i cant connect to the internet because there are no seettings for my country(zimbabwe).any help is much appreciated.i'm using a nokia 6600.

your net connection

If you connect to the Internet using phone as Internet device Ubuntu will use ethernet usb connection and only your phone will be using GPRS...
If you can browse Internet by the phone you should be able to connect using "shearing" internet setup - read the manual of the phone.
If the phone on its own does not connect to Internet - speak to your GPRS provider to find the proper settings of the phone for the service.
I wish you luck.