What is a good mouse/rat control method that won't harm my cats?

We just moved to a new house, and we can hear mice inside the walls sometimes. My two cats are outdoor cats and of course they catch their fair share of the mice, but I want to speed up the process and get rid of these pesky things. I don't want to use a poison or anything that could hurt my cats if they eat a mouse who ate the poison. What is a good pest control method that is cat friendly?

I don't know of any, although someone else may.

Is there a way your cats can spend time inside a few hours a day.  Even if they don't catch the mice, the mice will become aware of them and hi-tail it out of there.

We use live traps - one cat plays with a mouse, the other isn't interested in indoor mice. Just don't release the mouse out the front door - it will be right back inside. This one, with a slice of seedy bread inside. 

I agree with both ondine and cocheezie.

If you can close your pair inside for a couple/few hours at night, soon enough the mice will be history without having to be caught, as long as your cats are interested in mousing, but it sounds like they are.

Also humane traps are great!  I'd take a small piece of bread and put a plop of peanut butter, which can be smelled VERY fast, and they LOVE it, then let the poor critters go outside but away from the house.