WHAT IS A PODCAST? A podcast is simply an audio -- and sometimes a video -- recording made available online. The word is a combination of the words "broadcast" and "iPod," Apple's MP3 player. But, don't let the word "pod" throw you; you don't need an iPod or even an Apple to listen to existing podcasts, or to make your own. Currently, there are three types of podcasts: A basic podcast contains only audio and is the easiest to create and listen to. An enhanced podcast has both audio and slides (like a narrated PowerPoint presentation on the Web). A vodcast (or video podcast) contains video and audio and is the most difficult to create and view. Although some podcasts are one-time productions (Here is my lecture on the ramifications of World War II.), many podcasts are "serial" -- new episodes are produced each day, week, or month. Think of your favorite op-ed columnist in your local paper and imagine that he or she recorded the column daily. You even can set up your MP3 player or iTunes player to look for updates of a particular podcast. Let's say a local sports commentator presents a podcast of high school football games every Saturday morning. You could have iTunes or your MP3 player look for that update and have it ready bright and early the morning after your son's game. Next: How much is it?