@smokey @simonwoods I find that many larger podcasters are using third party platforms for hosting and distributing their podcasts. Many of these often use JavaScript trickery to hide the actual audio file of their episodes. Along with Cory Doctorow, I've complained about this before. There's a link in there with a Cory tweetstorm that has some cluse for how to find mp3 files for podcasts using iTunes.

Others have recommended one of my favorite tools: Huffduffer. It's got a couple useful bookmarklets that will help to find audio files as well as Ryan Barrett's Huffduff-Video bookmarklet.

Another service I like is Listen Notes, which has a podcast search functionality and will point you directly to RSS feeds which will also uncover audio files a bit more easily.

I found many of these to help create faux-casts on my own website of things I've listened to.