Once you understand how all the iTunes tags fit into the big picture of your RSS feed, it's time to implement them within your feed. Some of these tags are specific to the <channel> section of your RSS 2.0 feed and some are specific to individual <iten>. In order for any of these additions to work, you must designate a link to the Document Type Definition (DTD) for the iTunes namespace changes. In a standard RSS 2.0 feed, the namespace definition looks like this:
<rss version="2.0" xmlns:blogChannel="http://backend.userland.com/blogChannelModule">
This tells aggregators to interpret your feed as an RSS 2.0 document and display it accordingly. Adding the iTunes DTD for podcasting requires you to include a second xmlns: tag within the rss definition space like this:
<rss version="2.0" xmlns:blogChannel="http://backend.userland.com/blogChannelModule" xmlns:itunes="http://www.itunes.com/DTDs/Podcast-1.0.dtd">
Make sure you do not define rss twice like the example below because this will break some aggregators:
<rss version="2.0" xmlns:blogChannel="http://backend.userland.com/blogChannelModule">
<rss version="2.0" xmlns:itunes="http://www.itunes.com/DTDs/Podcast-1.0.dtd">
