If you're a history-buff like me, I can suggest two very well-produced podcasts in mp3 format. You can either go to iTunes and search for the podcast for subscription or you can go to their respective links to get the files. All the audio files are
free for download.

The History Network's Military History podcasts present the topics in a straightforward, sort of textbook manner; nevertheless, you'll relive the foreground and background sceneries of significant warfares that changed world history. They're mostly less than 30 minutes (the longest I know is 25 minutes) in length. It already has more than 500 episodes tucked in its library, with its early episodes being sold in DVD format. In addition, they also have podcasts in Ancient Warfare. To find out more, click on the image above. I score this a 4 out of 5 stars.

The Pritzker Military Library's podcasts are taken from live interviews of well-known military historians, fiction and non-fiction authors, and well-known military figures. Although most topics are seen in the American perspective, you can still learn much on the people who saw, felt, heard, and smelled war. With these considerations, I give this a 4.5 out of 5 stars. The mp3 files can be downloaded in iTunes, or from the website. Streaming audio is also available. Click on the image above to go to the website.