You need to get iTunes to pull your podcast feed rather than you site feed.
There are 2 ways to do this:
1. (the best way) is do do a 301 redirect See:
http://create.blubrry.com/manual/syndicating-your-podcast-rss-feeds/changing-your-podcast-rss-feed-address-url/ This will also change it for everyone (not just iTunes)
2. contact iTunes (support.itunespodcasts.com) and ask them to change your feed in their system to the /feed/podcast/ one.
Again, it's better to do the 301 redirect as it will get everyone rather than just iTunes.
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Mike
Lead Tech Support
Blubrry.com