Podcast not working as expected

We have a podcast and all seemed to be working correctly until we started adding messages in a second category. Now the links on our menus appear to return the correct filtered list for our first podcast, but our iTunes users are seeing messages from both categories. I think I need to go back and check the URL I submitted to iTunes. It may be incorrect.

Ïf your current podcast URL is without an Itemid, then it will always show all sermons. If it has an Itemid assigned, you can set a category filter in the menuitem with the same ID.

If you need to change the URL, you can use the "iTunes: Redirect" parameter. Put in the full URL of your correct feed there.
Or you can use the Joomla redirect component to redirect the old URL to the new one.
iTunes should pick up those redirects and adjust the podcast URL accordingly.

I'm sorry, I don't understand where I get the ItemID. I have a menu item for the RSS feed and I have specified the category that I want to limit the RSS feed to, but it does not seem to pick it up.

How do I find the proper Item ID and where do i specify it. Can you give me an example to look

The Itemid is the ID of the menuitem. You can see that in the menu manager.
It should be part of the URL like &Itemid=123.