I cant speak for WinAmp but I can offer advice in Windows.
First, Go to Control Panel, Sounds and Audio Devices, Volume Tab, Advanced button, and make sure you are setup for surround output.
You didn't specify what audio system you have, but on my Yamaha I just enable 5.1 output and use the ProLogic mode of proccessing to generate 5.1 audio.
IF Winamp could do it by software it would probably take up more proccessing time than you would like in the backround. And may not sound as good anyway.
I agree Creative Labs little backround programs should be a last resort.
Tell me what speakers you have. Most good 5.1 systems have the ability to jump back and forth between 2.0, 2.1, 4.0, 4.1, 5.1 and 6.1 with no quality loss. Some can even differentiate stereo sounds and make them seem like true surround.
I use the Yamaha Cavit RP-U200 system.
http://www.yamahamultimedia.co...ducts/cavit/rpu200.asp
While not very powerful the control over audio I have is amazing.
When I close the software the settings are kept in the reciever, even if I unplug it for a week. Also has a good variety of inputs and outputs for such a cheap system.
I use an Audigy Platinum Ex. Digital Coax and Fiber Optic cables both sound the same.