Clone script

I’m programming a script for Blender 2.5 and I need to create a clone of the active object. May be following the path of the mouse pointer, or distributed along a curve painted by me.
How can I do???

If I program an operator I can control when executed a mouse click, also I can capture the screen coordinates with functions, "muose_x " and “mouse_y”, but if I want to create a cube where I click, the screen coordinates does not serve me to this.
What should I do to locate the cube where I click? :confused: