Stereo and Surround Sound Speakers by: Paul - The Home Cinema Guide
Tim
You certainly can.
A 5.1 surround sound speaker system will have 6 speakers - front left/right, centre, surround left/right and a subwoofer.
The front left and right speakers are effectively your stereo speakers. Anything you play through your system which has only stereo sound, will just come through the front left/right pair (and the sub).
Just be aware, surround sound speaker packages can sometimes lack audio quality compared to a good pair of stereo speakers. If you need great stereo audio too (primarily for listening to music), then either pay a bit more for a higher-end surround package, or buy your surround speakers separately and spend a bit more on the front left/right pair.