I can't remember if I had to install gppp on 9.10 It is required for
dial up and that is how g3 cards work. You must set up your connection
but should only have to select the service you have to make the thing
work. Sprint has a tutorial on their web site that should help you.
When setting up your service check the button that says something about
auto reconnect.

I would suggest upgrading to 10.04 that has better support for almost
everything. I have noticed an almost plug and play with all my hardware
that gets better with each upgrade. I also have a 760 on different
network, but have installed ubuntu on others equipment using different
dongles and they use the same procedure to connect to the net.