Can an AirCard connect once Windows has booted, but before a user has logged into Windows?
If so, would you please reference more information.
Though I have very little experience with Windows startup scripts, this may be the way to do it. XP/Vista is more than capable of managing the dial-up connection. A batch file can "open" the actual or a shortcut of the network connection, which will essentially connect to the network.
A little study on startup scripts and I think you'll be in business. Here are the instructions on creating a dial-up connectoid:
To set up a manual dial up connection in XP/Vista:
Network Connections> New connection wizard
Connect to internet
Set up manually
Name it whatever you like
Phone number is #777
The username is firstname.lastname@example.org
The password is vzw3g.com