I listen to a lot of podcasts. Sometimes they start to pile up, and I want to get through as many as possible. I decided that I’d make a smart playlist just for such occasions. This smart playlist will take all of the podcasts that haven’t been listened to, and put them in order of oldest to newest.

Launch iTunes, and click “File > New Smart Playlist“.
The file menu in iTunes.

In the smart play list setting, make two rules. 1) Podcast is true. 2) Play count is 0. Click “Okay,” and name your smart playlist “Unheard Podcasts.”
The Smart Playlist settings window.

Now navigate to the playlist you just created, and press Command + J to bring up the view options. Make sure the only check boxes are: Album, Artist, Release Date, and Time.
The "View Options" window.

Click “Okay,” and then click on the box in the top area of the iTunes window that says “Release Date.” Make sure the arrow is pointing upwards.

Now all of your unheard podcasts are in order of oldest to newest for your listening pleasure.