i want to play my music out of my laptop through my surround sound system. at the moment i've just got a headphone jack to red and white phono. is there anyway i can export it using the usb port because sometimes when i turn the headphone jack different speakers come on and off!.

Sure - there are lots of USB DACs available - although I think most are 2 channel - if you want surround you may need to add the surround processing in your receiver/processor.

I run this out of my home PC: http://www.tascam.com/products/us-144.html

Which works pretty well for my purposes (I've gotten a couple blue screens under XP, but it's rare enough I haven't tried to figure out the driver conflict) - you can find it at a Guitar Center/Sam Ash type store for ~$150 I'd expect. It does a good job of making my iTunes library available in stereo to my Surround setup.

Lots of headphone Amps have USB interfaces as well & there are some very expensive USB DACs depending on what you want to spend. You might find more/better info at head-fi though in the Computer Audio section: http://www.head-fi.org/forums/f46/ - the EMU 0404 is very highly recommended there - I started off looking for one but found the Tascam to be less expensive and in stock when I was shopping locally...