How to get direction using Physics.SphereCast ?

The question is very simple, but it makes me mad, just need to get the direction for game object which is under character controller. Is there any example to illustrate how to get the direction?

transform.forward
http://docs.unity3d.com/Documentation/ScriptReference/Transform-forward.html

There is also transform.right, and transform.up.
http://docs.unity3d.com/Documentation/ScriptReference/Transform.html

-transform.forward is backward. -transform.right is left.