Building a Soccer Robot using Arduino and other technology

I have planned to start with 'half' of the total play area: 4 x 3 ft with only one goal. The camera is located 4 ft above the field. Throughout this project, I attempt to explore the integration of cutting edge technologies like XBee (2.4GHz RF), micro-controllers, vision software, math and computing. I thought of a soccer robot to make it friendly. Let me tell you, I don't know if the size of the field will be enough for the corrected trajectories of the robot or if tomorrow I am going to need a better micro-controller or vision system, but so far, my project has become more complex and exciting!