GM steering wheel controls

My Mother has asked for my help on an issue. Yes, my mother. :) SO she has a 93 Park Avenue. It has the factory controls on the steering wheel. She is getting on in years and loves the idea not having to reach over to the radio and drive both at the same time. I have heard that there is a inline controller that works with a hand held remote system on your head unit. Can anyone tell me where I can find these? Thanks for you imput.

Man... Old people and their steering wheel controls.

http://www.pac-audio.com/