"In Ubuntu you can setup the modem-connected machine as
a robust router/firewall using the in-built Network Manager,
Firestarter, and optionally, Gadmin DHCPD. These are all GUI tools
and so there is no need to go near the dreaded command line here.
"With the release of Ubuntu Jaunty Jackalope mobile broadband
setup has become very easy and intuitive. Simply plug the modem in
and in a few seconds the "New Mobile Broadband Connection" wizard
should appear. Click "Forward" and you will be presented with a
list of mobile broadband providers relevant to your geographical
location. Select the provider you use and click "Forward" again.
See Figure 1."