I think there was a spec-wise listing at one of the big players' (National Semiconductor mebbe) sites for Audio Amplifiers...

Also do a google on "audio amplifiers", and you might also add "hobby electronics", you'll get lotsa circuits.

I once made a Power Amplifier using an op-amp and a power transistor (Tip 122), but I am sure there are much easier and better solutions out there.

kundi