Podcasts are great for travel, they replace cassette tapes of books or radio shows I used to tape for long car rides. Now I down a podcast or two to my MP3 player and listen in the car with headphones or the cassette player insert that connects to my player. I can have the NPR shows I like whenever and wherever I want.
In our school the students podcast as a part of the curriculum. They have done advertisements they have written and history reports. They enjoy the writing, recording and editing of their group's work and the presentation.
I found a podcast, Storynory, that has stories for children. It would be a good listening center activity as well as entertainment in the car. I found lots of podcasts I'd enjoy myself if I had the time. My 5 minute commute isn't conducive to much listening, but I would use podcasts on a longer commute.
I actually think podcasts are one of the more useful gizmos we've tried. They are available on so many topics and are reasonably easy to create making them a useful tool to disseminate information on a website.