to do what? anyone can connect a webcam to a robot
(well, not really...)
but, different circuits will give different results...
some are better than others for certain purposes.
but one things for sure, camera processing requires big @$$ electronics...
what do you want yours to do?
check out http://www.societyofrobots.com/robot_faq.shtml#camera_microcontroller
i really recommend the blackfin as admin and others have info and code on the site that will help you get off the ground.
but as i said, blackfin is almost plug'n'play as it does the processing for you.
most microcontrollers cannot handle this feat and this is why most people use an onboard laptop
for this kind of stuff.