Tell him a podcast is like a radio program. You have to have an application to subscribe to it. for iphone itunes handles podcast. For Android devices Listen is the best podcast manager. You can search from the application on the types of podcasts you want to listen to. If you subscribe to that show, the podcasts automatically appear on the new podcast list. you can set the podcast to either automatically download or you can manually download them.
For example you can search for cnet in the search box. Cnet has couple of podcasts like Buzzout Loud, Android Atlas, the 404 etc, click on it and you can listen to it, you also have the option of subscribing it for future shows. 
Most of the podcasts are free.