If you maintain your own website, it's as easy as using
* Build your feed by inputting all the pertinent info it asks for
* Host your assets on a website (in most instances, I personally just use wordpress and throw mp3s/jpegs and direct link to them in the feed)
*Upload the newly created rss.xml file onto your website
*Go to 
and paste in a direct link to the feed here and boom within a couple of minutes the podcast will start to populate in the apps.
I've used @StevenB 's tools to upload over 100 different rss feeds and can attest to these steps. Please hit me back with any questions.
Sovereign Feeds
Own your feed, own your life.
Podcastindex.org
Add Feed | Podcastindex.org
The Podcast Index is here to preserve, protect and extend the open, independent podcasting ecosystem.
Direct link to the .xml file: 
