3 circles intersection

Hi,

I was thinking about the following problem and couldnt find a decent
solution for it.

If I have 3 circles that intersect like this:
http://tomerbd1.googlepages.com/circle.intersection.JPG

How can i find exactly in some math way the area where all 3 intersect
in and the central point of intersection of all 3 circles?

Thanks

Tomer