2d to 3d mouse?

I want to create a plane or flat mesh with a grid and atach
it to a plane (another grid) in the y coordinates while being able to move it in the x and z direction with the mouse,you know like in maplet.
How could this be done?
I can already do it with the direction keys but not with the mouse. Is this realy complicated?
I have already looked at a couple of examples in the code archives but those don't seam to be aplicable.

Use the MouseXSpeed(), MouseYSpeed(), and MouseZSpeed() commands.

Note that MouseZSpeed() works slightly different than X and Y.