Another new feature in iTunes 4 is the ability share individual track URLs.
With sharing enabled in the preferences panel, control-click on a track in your library to bring up its contextual menu.
Select ‘Copy Sharing URL’ and paste it into an HTML document or an email.
This is particularly useful if you produce your own music; you can publish track URLs and serve them up from your own iTunes library. *[URLs]: Uniform Resource Locator