I've created a RSS 2.0 feed for my podcast, but when I test it in iTunes (Advanced -> Subscribe to podcast..) no episodes are showing.
I haven't yet added iTunes specific tags, since I though they were not required. Are they? Is there any way to debug why it's not working? It is a valid RSS 2.0 feed according to W3C's feed validator.
The <link>s in your <item>s should be <enclosure>s instead. See the feed specs example feed:
<enclosure url="http://example.com/podcasts/everything/AllAboutEverythingEpisode3.m4a" length="8727310" type="audio/x-m4a" />