Using cameras on your robot isn't too hard, as long as your computer or robot controlle can handle the processing power required for computer vision.
If I were you, I'd try getting a nice webcam, and using Roborealm. Roborealm is an absolutely free download. Just google it, and check it out. It should have everything you need for hobby robotics vision processing. They're always adding new features too.
So what to do?
1. Get a computer or microcontroller that can run Roborealm.
2. Get a nice performance webcam and interface that to your computer or microcontroller.
3. Download Roborealm, experiment a bit, read some nice tutorials on their site...etc.
4. Try out your robot