How To determine the Motor for Robot?

[birdchee]

can i know how we determine the motor for a robot in general, and another with the following specs.
- directional ( can turn, reverse)
- continuous moving
- moving in constant speed except turnning
- weight around 1KG
- small in size
- using low voltage battery, typically smaller than 9v (maybe even smaller than 5v battery)
what motor is suitable for this kind of robot? how we know the motor is suitable for the robot.

And regarding the rating for a motor, what is meant by Torque :  1.6Kgcm

thanks in advance 1st.

[pomprocker]

http://www.societyofrobots.com/calculator.shtml