[Princess Garnet]

if you want to fix this you need to buy a gaming keyboard as they often have no such limit.

It has nothing to do if it's a "gaming" keyboard or not. The three key limit is a limitation of the PS/2 connection, so using a USB keyboard, any USB keyboard, will allow you to press more than three keys simultaneously.

Speaking of this anyway... I'd like to get a USB controller of any kind that can be configured to work with pSX.

The only usb controller I've heard of is the Windows Xbox 360 controller. Would it be possible to config that controller for an emulator?

If you want a controller, while the Xbox360 controller is good all around, if it's for Playstation emulation specifically, I went with one of these.

Newegg.com - Logitech 963325-0403 RumblePad 2 Vibration Feedback Gamepad - PC Game Controllers

If you won't mind missing out on rumble, you can save a few bucks with this one. It's the same thing minus that.

Newegg.com - Logitech 963292-0403 Dual Action Gamepad - PC Game Controllers

I have both, and both work flawlessly for Playstation and Playstation 2 emulation.