put the mp3 in a folder called media or something like that under your www root directory, then you create a text file, you put the path to the mp3 on the first line of the file, example
you put track1.mp3 on your website at
www.mysite.com/media
you would have to edit the text file with
http://www.mysite.com/media/track1.mp3
then save the txt file as track1.m3u
you create a link on your site using the track1.m3u.....it will automatically stream your mp3 ....you don't actually need the full path if you have the file in the same directory.