Last year I had the opportunity to get two laptops up and running with Verizon AirCards (the model number escapes me at the moment). The only real "trick" was that in order to activate the card we had to use Verizon's Windows software.
After it has been activated the card appeared to Ubuntu as a USB modem. All you need to do at this point is configure a modem connection to the internet using that device. In Ubuntu you go to System->Preferences->Network Connections then click on the "Mobile Broadband" tab.
Just installed the 9.10 distro of Ubuntu the other day and it configured up just the way you said. Very simple matter of just selecting the the G3 broadband provider under the Mobile Broadband tab and telling it to connect. And it did it...very quickly!
From a pain in the ass to painless. I'm impressed.
Thanks for all the help everyone.