[G4] Sound Processor for a G4

[rich northouse]

Hi Folks,

Hope every one had a Happy Turkey Day.  More than the turkey is stuffed 
at our home.

I have a G4 733 MHz (silver something) with a DVD -/+RW running 
OSX.3.6.  I have had a set of speakers for it for over two years but 
have never got around to hooking them up.  I would like listen to tunes 
and perhaps play a movie DVD.

What do I need? There is a speaker and earphone jack on the rear of the 
system box.  Do I need a USB sound processor of some sort to get 
surround sound or pseudo surround sound?  My set of speakers includes a 
sub-woofer.

Your help is appreciated.

Thanks

rich