Currently, iCam supports USB/Built-in/Firewire webcams and Ethernet/Wi-Fi cameras. For the USB/Built-in/Firewire cameras, the iCamSource program asks the operating system for a list of available webcam devices, so if your device isn't showing up, the operating system probably doesn't consider it a webcam.
Check to make sure the drivers for the device are updated to the latest version. A couple users have gotten non-webcam devices to work by updating their drivers to the latest version.