I thought of using adns 2610 sensor with hdns 2100 lens and interface that with arduino board..Or i thought of using cmucam with arduino board..which would be a better option and how should i go about it ??
The ADNS-2610 would probably work but you wouldn't want to use the standard lens. It's designed for focusing on surfaces within an inch or two. You probably want something like a webcam lens to focus on more distant objects, the wider the angle the better. Also the 2610 is obsolete as of January 31st, 2011. It was replaced by the ADNS-5050 or ADNS-2700.
The ADNs-2700 is a one-chip USB mouse so that would not be easy to interface. The ADNS-5050 has the same 2-wire serial interface as the old ADNS-2610 so that would work. I would get the ADNS-3000 because I'm more familiar with the SPI serial interface than of the 2-wire serial interface.
CMUCAM would be WAY more expensive ($100-$200 each) than an ADNS-3000 chip ($1.56 each from Digi-Key)