random spawn help

i have very little scripting/programming knowledge and would like help with a script that means that when i click an object it jumps to a random x,z position on the terrain. Could anyone help?

http://unity3d.com/support/documentation/ScriptReference/Random.Range.html, the only diferent would be to set the spawn position on the variable position.

var newposition = Vector3(Random.Range(-10, 10), 0, Random.Range(-10, 10)); 
spawn.position = newposition;