Connecting to GPRS using a Nokia Phone is not too tough in Ubuntu Gutsy. This is because the default udev rules does install the required drivers and map most of the Nokia devices to /dev/ttyACM0. But it can become tough if you need to retain the resolv.conf or making the pppd to add a default route to the connected device. We will see how it was done properly in the Saturn Labs.
First of all the gnome-ppp which the experts at Saturn Labs installed was found to be buggy, as per the bug stated here. This bug is related to the change in logging by wvdial. Though it frustrated the people at Saturn Labs, once the patched version is installed, gnome-ppp will start working.
If you do not have another networking configuration, then this should be okay and GPRS should be working properly refer to the config file attached. If by any chance you have another network, and a default route attached you might find that the pppd refuses to change the default route to this device which is now connected. For this you add one line to /etc/ppp/ip-up, just after the parameters are assigned to human readable variables: