How you animate a wheel?

Hi,

as simple as it sounds, but how you animate a Wheel, or let`s say generally, a Circle?

The Main Problem I have, is how to make the rotation of the wheel properly.

For example, you want to animate a car from side View who accelerate from 0 to 100 mph, then he holds this tempo for 5 seconds and then he brakes smoothly to 0 mph.

But forget the car itself, just concentrate on the wheels.
How you animate this?

PS: Sorry for my bad english.