I have a Cat CDMA Sierra 580 Air Card and I recently had a visitor to my house and it became a war over control of the keyboard. Does anyone know how to connect two laptops to one air card? Internet connection sharing?

If you are running Windoze, I believe it is possible to share your network connection (i.e. the one that is using the AirCard). Right click on the network connection icon for the AirCard, and check if there is an option for this. You may need to examine the properties of the connection if it is not there.

I've shared a network connection before (when I was using dial-up service in BKK), and I believe the principle is the same with the AirCard network connection.

connect 2 laptops with peer to peer wifi connection (google on how to do it)

and share your cdma connection

it's not really difficult even for the first time, you may need to reboot and/or run network setup wizard on both laptops if it doesn't work immediately