The San Bernardino County Sun recently published the article Getting Tuned In. It tells about the use of iPods at Clement Middle School. The iPods are used to listen to recordings of literature instead of listening to them on tape or CD. The article mentions great uses and benefits of digital audio for learning. The school uses audio from the audible.com service, so they are paying for the recordings.
iPods are great, but it's important to note that everything mentioned in this article could also be done with Palm or Windows Mobile handhelds. Think about this: The iPod Shuffles used at Clement retail for $99 and do not even have a screen. For $129 (for the Palm Zire 31) plus the cost of an SD card, students could listen to digital audio while illustrating it, writing about it, taking notes or a quiz, or reading along all on their handhelds. For just a little more than $99, you can supply students with a fully-functional computer instead of having limited the use to digital audio.
The biggest advantage for using an iPod for digital audio is its seamless integration with iTunes. The moment you plug in the iPod, iTunes syncs podcasts and playlists to the device. It's not as seamless when using a Palm or Windows Mobile handheld computer. I prefer to use an SD card reader and copy the audio files from my desktop computer to the card. When I insert the card into my handheld, I can listen to the audio in pTunes, Real Player, or TCPMP. Read more about using your handheld as an MP3 player at K12Handhelds. And this is really handy: Mac users can use the free software SyncTunes to simplify the process of syncing mobile devices and memory cards to iTunes (Note: You won't be able to play songs you have purchased through the iTunes music store because they are copy-protected.)
Rest assured, whatever you use for listening, digital audio is a great tool for learning.