Podcasts make me think of the "olden times" when families would gather to listen to a radio show. Some podcasts even use similar effects to enhance the broadcast, i.e. sound effects, music, etc. I like to use podcasts in my classroom. Each spring I have students create podcasts in which they explain commonly misunderstood grammar concepts, such as who/whom. I prefer podcasts for this because they really have to understand the concept to be able to explain it clearly to others without the use of visual aids. They also have to pay close attention to what they are saying and how they say it. Plus, the podcasts are so easy to create and it gives students who are shy in front of an audience a chance to really shine, since they record in private.
One of my favorite podcasts is Grammar Girl. I reference her year round to my class. Here is her website that has all of her podcasts along with a written version of each podcast, for the visual learners, http://grammar.quickanddirtytips.com/. A podcast I found for social studies is World News for Children. It broadcasts current world news for kids. I love it for current events, especially since so few kids read the paper or watch the news. I have now linked it through my school web page for the students to access, http://www.learnoutloud.com/podcaststream/listen.php?url=http://downloads.bbc.co.uk/podcasts/bbc7/wnc/rss.xml&all=1&title=30653.