With a command module? That's gonna be difficult, as all the command module consists of is an AVR Atmega 168 micro-controller, and it's one Uart (serial port) is used to interface with the Create itself. When you plug the USB cable into the command module, it disconnects the Uart from the Create to allow flashing over the Uart.
So either the Command module is communicating with the Create, or it's communicating with the computer over USB, but not both at the same time.
I recommend using another micro-controller, like the Axon, that has multiple Uarts to replace the command module. That's what i did here. :
http://www.billporter.info/?p=160I can provide you a rough wiring diagram if you like.
Then you can communicate to the Create on one Uart, and with a computer over wireless like bluetooth or Xbee using another Uart.
They only other way, if you are tied to using the command module, is to try to implement a 'software serial uart' on the Command module's IO pins. Google around for ways to do that, but it's going to be complicated to program.
