OpenStreetMap is a free editable map of the whole world. It is made by people like you.
OpenStreetMap allows you to view, edit and use geographical data in a collaborative way from anywhere on Earth.
You can use this tool to find the radius around a point on the map. First type in the radius required (in kilometers) and then click on the map at the centre of where you wish the circle to appear. You can then create as many radii as you wish. (9/08: works in safari, but not in firefox 2)