I mentioned last week that the new release of Ubuntu (Intrepid Ibex) includes 3G Mobile Broadband networking, but there is a "small problem" with it. I was hoping that it would be resolved by the beginning of this week, but as of this morning it has not been. If anyone else has been trying to use this feature, and it doesn't work, feel free to contact me and I will send (or post) the details of the solution. Otherwise I won't bother putting a long explanation here for no reason.
In a nutshell, the problem is that the Network Manager is not able to properly set the APN during connection initialization, and the solution is to remove that information from the Network Manager, and either ignore it (for "branded" 3G cards which have that preprogrammed), or initialize it once in some other way.