Object.ray_cast returns hit_co, hit_no and face index:

http://www.blender.org/documentation/blender_python_api_2_66_4/bpy.types.Object.html?highlight=ray_cast#bpy.types.Object.ray_cast

New Scene.ray_cast should return hit_co, hit_no, Object (and face index?) for consistency / convenience (ok ok, you got me, it's a feature request...)

https://gitorious.org/blenderprojects/blender/commit/1a85a610582a32f37fa9b52268ad906ab1f56229