Podcasts are (normally) quite short audio or video files that can be downloaded to your computer/mobile device for playback later and cover a vast range of subjects/genres: radio shows, discussions, comedy programs, language learning - you name it, you can find a podcast for it. Here is Wikipedia's clear explanation of what they are if you are a little uncertain about them.
Podcasts are great for mobile learning because they can be carried on your phone and listened to when you have a spare minute, such as when you are walking somewhere, taking a bus, waiting for someone, and are a great way to learn in bite-sized chunks. What's useful is that you can subscribe to a podcast program or website (just as you would subscribe to a magazine or newspaper)and your phone or computer can check regularly whether there is any new content available.
Even better is that many mobile phones have applications available for them that allow you to search for, download and play podcasts directly on your phone without the need for a computer. If you have an iphone for example, you can download podcasts directly from your phone through the app store. Here's an explanation of how to do that. Most other reasonable modern phones will have a podcast application available for it. It will either come with the phone when you buy it or you can download it from the internet or the application store available on the phone. Don't feel obliged to pay for podcast software, it's normally possible to find decent podcast software for free. For example most modern Nokia phones come with software that allows you to do that, if not then it can be downloaded for free here.
You can see here my podcast app on my phone and the list of shows I've subscribed to.
So how can podcasts be used in the ESL classroom? Well, your students can be encouraged to download and listen to them on subjects they are interested in, or they can download podcasts specifically designed for ESL students. This is a good place to find podcasts directed at ESL students. As a teacher you can also download these and use them as listenings in the classroom.
Or they can be encouraged to go to a general podcast site and find podcasts that are on topics that are interesting to them. Podcast Alley is a great search engine for finding interesting podcasts.
In a future post I will also discuss how you can create your own podcasts for the students to listen to.