That's not done too much anymore as the sounds can be annoying to visitors who are not "in tune" with the tastes in music so most always there's a media player included (flash, etc.) so visitors can turn it off, but anyway.... here goes:

This is a quick fix for IE users, I'll look and see but I don't think it's supported in other browsers.

1. Load the music file
2. Call for the file in your header. (between the head tags in the HTML).