I take it you are linking to a file. Is that right?

What you want is for the headers sent with the file to say the Content Disposition is an attachment. That will tell the browser to download it.

If you're using apache you can do something like:

<FilesMatch "\.(?i:mp3)$">
  ForceType application/octet-stream
  Header set Content-Disposition attachment
</FilesMatch>

This will tell IE that it's an application file and other browsers that it's an attachment to be downloaded. In the FilesMatch part is a regular expression to look for mp3 files with upper or lowercase letters.

This would go in the directory of your files or one above it and in a .htaccess file. Or, it can go in your apache config if you have access to that.

In case you don't have access/authority to use .htaccess to create the needed headers, you could create a simple "view" page in php that creates the headers and outputs the mp3.

header("Content-Description: Harcourt Industries - {$fileName}");
header("Content-length: {$fileSize}");
header("Content-Disposition: attatchment; filename={$fileName}");
echo $mp3

The use will actually never see the view page since it contains no content - it serves as a download point (it can also be used to do data tracking - updates a table keeping track of what is downloaded and how much).