The US National Parks Service is getting into podcasting in a big way, and now offers 18 park service podcasts and virtual tours, offering hundreds of audio and video programs that you can get from park websites or iTunes.
The podcasts include:

Acadia NP
Antietam National Battlefield
Black Canyon of the Gunnison NP
Canyonlands NP
Clara Barton National Historic Site
Curecanti National [...]

The Valley Forge National Historical Park and energy utility PECO this week have announced the creation of the PECO Podcast Through History.
The Southeast Pennsylvania gas and electric utility has given a $20,000 donation which will fund the creation of a podcast series that can be accessed at the park or from home, that will guide [...]

The British monarchy dates back over ten centuries, but for the first time ever, this year, the Queen’s Christmas speech will be available as a podcast.
This year, the Queen has focused her Christmas speech on the relationship between different generations. Buckingham Palace described her theme as highlighting “what old and young have to offer each [...]

NYC Transit has launched TransitTrax, a podcast service for New York city Transit riders. The service will provide riders with the latest news, service advisories and security initiatives.TransitTrax podcasts range from MTA New York City Transit Lost and Found to If You See Something Say Something, a podcast about transit security.
Unfortunately, NYC Transit doesn’t appear [...]