Yes, a commodity is the OS2.0+ style of doing it. The 1.3 style is to install an input handler which removes the mouse events from the input stream. IMHO this is easier.
Still the RKRMs will tell you how to do it.
There are two other methods which will more or less annoy the user:
1. always move the pointer to an absolute position whenever you need it. So the user can move around the pointer but you will force it to the desired position when needed.
2. let the user move his pointer as he likes (or make it invisible) and draw your own pointer into your application's window.
Bye,
Thomas
