After weeks of searching for a clean audio amp install for my cab, I came across these nice kits from CanaKit. I used the UK194 bridged 20W stereo amp which accepts a 12V/2A power supply for which you can find a medium sized wallwart or use a fixed power supply.
http://www.canakit.net/Contents/Divisions/Div_56.aspI didn't want to go the PC speaker route as I I didn't like the way it looked and have no need for a subwoofer.