Podcasting now comes in several varieties. A podcast is like an audio file, an audio file with pictures, a video file, or a combination of these. You can subscribe to a podcast via an RSS feed.
iTunes is a great way to find thousands of free podcasts to watch. It will also let you listen to and watch podcasts that you make yourself. And for those who like to share with the world, iTunes makes it possible to publish your podcasts globally.
Audacity is an excellent application for making audio files on a Windows computer. If you save in mp3 format, you can upload the file to Sayre's Media Manager and link to it in your website.
GarageBand is THE application for making audio files and all forms of podcasts on the Mac. It uses mp4 formatting and will put your podcast directly into iTunes for you. You would need to convert to mp3 to make it available on Sayre's Media Manager.
For education, the SmartBoard recorder is a great tool for recording both your voice and your desktop, so you can teach a lesson on the computer and save it as a movie. To make that movie available on Sayre's website, you need to import it into Macromedia Flash and export it in swf format.
Many excellent tutorials on podcasting are already available via the web. Here are a few that I investigated.
A How-To video for adding to Media Manager
Instructions for creating a video using SmartRecorder and making it available on Sayre's Media Manager.