Questions regarding receiving 3G calls on my IDEOS
You will not be able to receive a 3G video call from another phone, assuming what you are looking for is the operator backed 3G-324M solution that is available on most 3G phones (not including iPhone or Android).
3G-324M as a solution doesn't run over IP and requires a tighter integration between operating system, modem and application.
You can read more on the technicalities here: http://www.radvision.com/Resources/Developers/White-Papers/android_integration.htm