I have a mouse or two around that connect via USB. Is it easy to install one of those...and is it easy to go back to a PS2 mouse if I wanted to?
Thanks.

As easy as plugging it in and turning on the computer. Sometimes you need to install a driver but it's been my experience that it's seldom necessary.

To switch from usb to ps2, shut down the computer, switch the mice and start up the computer.

Some people may see me as a stick-in-the-mud for this, but my own feeling is that as long as PS/2 keyboards and mice work OK, and you have PS/2 ports in your system, why bother using two of your USB ports for those devices? Get a good PS/2 keyboard and mouse and save the USB ports for other devices.

I use PCs with both, you just have to remember to shut down when plugging in/disconnecting a PS2 mouse to avoid permanently damaging the chipset on the MB.
I prefer USB mice for notebooks as I can plug it in/disconnect while running and the driver is already there in XP for the mouse. This way I can start the boot process and still be plugging in the mouse and power adapter while XP loads.

you can get a usb-to-ps2 connector from any computer supplier for a buck or two... gives you the best of both worlds. most stuff you buy no is usb and inlcudes the little adapter

yes, I have a couple. That's what brought this whole thing up. I saw that on a mouse I have, but haven't used and thought maybe I'd try it. But as joea64 said, I might as well save the USB ports.