Are we talking 3G? Many a dongle has memory for setup drivers.
Unmounting this memory that shows up as a drive, gives access to the 3G
system. Most work using PPP to connect. If you edit the connection you
can check the automatic reconnect box and Ubuntu will reconnect if the
connection is lost. On 9.04 and 9.10 I had to install the GPPP apt. In
10.04 the PPP apt is already installed.

Using a 3G card in Ubuntu is not all that hard, I found instructions on
the Sprint website and setup at least 10 systems using them.