<?xml version="1.0" encoding="iso-8859-1" ?>
<rss version="2.0" xmlns:itunes="http://www.itunes.com/DTDs/Podcast-1.0.DTD" >

The 'xmlns' declaration is supposed to give a 'dictionary' of the document language so that an absolute stranger to the itunes namespace can figure it out. I'd have to go dig up the xml spec, but I'm pretty certain they say in pretty strong language that if you sponsor a DTD, you kinda' gotta' haveta' put it at a URL that is never going to change. Ever. This URL comes straight from Apple's own Podcast spec (which coincidentally was invented by MTV veejay Adam Curry, who will soon be the father of the internet according to wikipedia).

Yet if you go to that web address and try and read the language definition, you'll find yourself instead at apple.com/itunes staring at an Apple eShopping mall and in my case telling me that I need a new operating system to install iTunes. Where's the DTD? In fact I'm just trying to extend RSS in another way and was going to use their DTD document as a template (since it's about the only existing extension onto the RSS space). Sigh...