To share a LAN connection over WIFI the easiest way is to use an Access Point. (You could even just use a router and ignore the WAN port). While it is technically possible to use a USB WIFI adaptor, you will need to find a way to bridge (rather then route) the connection. I don't know how you would do this with Windows, but in Linux you would use the "brctl" command. (This link may be useful).
A CDMA connection can't be shared over WIFI as it is a different protocol. There may (or may not - we use a different set of standards in this part of the world) a "PICO CELL" device you can buy / lease from your carrier which will allow you to use your Internet connection to back haul your own minature cell tower (thats what the PICO cell is) back to the Cellphone network.