Measuring distance if on a bike

How can you measure distance between one stop and another. I see the pedometer is available but this will not work if on a bike.

using GPS?
or what are you trying to do?

I was thinking using accelerometer. But would the gps be the best shout. How would you test distance and speed on a bike. I kind need a Pedometer plugin but for a bike.

I would use gps and calculate the stats, you could also make/modify a bike speedometer - they work by counting the rounds of wheels. With a magnet on the wheel and a sensor that triggers every time the magnet passes it. So you could have nearly perfect stats for the people that buy your gadget and connect it to their phone.