Somthing I found while looking for something else (from MS).

"Mouse Wheel Tips

Here's a handy new feature in Flight Simulator 2002: If you have a mouse with a wheel, you can roll the wheel forward and back to change frequencies on the radios, set the heading bug and autopilot settings, change the “squawk” code in the transponder, and operate other aircraft and avionics controls (trim, flaps, landing gear, light switches, and so forth).

To use the wheel, point to the item you want to change. When the pointer changes to a “+” or “-“ roll the wheel.

You'll often find using the wheel is faster and easier than clicking the left mouse button. "

I really love my track ball mouse, but that sounds like a very good reason to go back to the old wheelie!

Thanks for the tip, WPA!

Now that IS a handy tip!

Ozzy