How can I find the RSS feed from an iTunes URL?

The iTunes feed will contain a number, of 6 to 9 digits.  Simply take that number (the podcast ID), and replace it in the URL :-

https://phobos.apple.com/WebObjects/MZFinance.woa/wa/pingPodcast?id=272839370

This will show you what the actual RSS feed is, as well as initiate a “ping” to iTunes to refresh the content on the iTunes music store.