Here are a few ideas for making podcasts for your students:
1. Make recordings of your experiences like the time you met someone famous or thought you were going to die in an accident. Don't be boring but be simple.
2. Interview friends and other teachers. Don't rely on the friends to be simple enough or talk slowly enough. If the friend is using some language that you feel is too advanced for your students then jump in and ask your friend to define it or define it or restate it yourself.
3. Take your students on a tour to a favorite local haunt. There is a shopping mall here that is immensely popular with all students in this area. Record a tour of the location that they could listen to and use to follow your footsteps. Describe what you see, tell some funny stories and go in to the shop and talk to some clerks about their products. I did this with my notebook computer in my bag running Audacity with a microphone clipped on my shirt. Many mobile phones have recording functions on them. You can include some insights into some of the businesses or some of the fashions even if you have to look them up on the Internet. Check this out.
4. Make your case for your method. Students always want to know what is the best/fastest/easiest way to learn English. Explain how you are teaching your students. Some of our teaching methods are counter intuitive. I think Grammar-Translation makes a lot of sense but is not as good as Communicative Approach. If our teaching method is not always easily accepted by students you should take every opportunity to "sell" your teaching methods over and over.
5. Don't just make a recording on any subject but try to steer it in a way to augment units you are teaching in one of your courses. This way you can further the unit, even if you have to 'assign' the listening item, or you can use it as a collection of materials students can listen to on a voluntary basis. For example, if you have a unit discussing Human Resources you can interview a friend about their experience in hiring or with working with colleagues.
6. Record your lessons. This is normally quite boring but it can be very effective if you just extract some of the jewels, ancedotes you tell your students, special tips on learning English, fun facts, a story about your travels, etc.
I am also trying some projects along this line and am starting to post them at GCAST.