I recently set up an RSS-like feed for use with the iTunes store, for distributing media files as a podcast (or “vodcast”). I did some searching for existing PHP scripts to accomplish this, and came across Anis uddin Ahmad’s Universal Feed Writer classes. They can be used to create RSS1, RSS2 and ATOM feeds. I extended his classes so that they can produce iTunes feeds as well, which is a major departure from standard RSS (it has it’s own DTD). I’ll send them to Mr. Ahmad too, in case he wants to add my updates to his files. He didn’t specify any license, but did mention “Share and Enjoy” at the bottom of his blog post, so I’ll do the same: Share and Enjoy! Without warranty of any kind. :)
The iTunes extensions to RSS2 are helpfully specified by Apple. The process of getting the feed set up and into iTunes is laid out in four easy steps by Derik Whittaker. Note that you can create an URL that will open in iTunes so that it connects directly to your site (without going through the iTunes Store), using this format: itpc://FEEDURL.