When we last talked about podcasting, we basically established the fact that there is really no mystery in this audio craze. Simply, a podcast is nothing more than an mp3 audio file that's "parked" on a web server along with a file that describes what it is. That file is called an RSS file and you can sort of think of it as being the digital equivalent of a CD cover. It's a description of contents. RSS stands for Really Simple Syndication (file extension .rss) and what it does is spell out in Internet language the "who, what and where" of the audio show contained in your mp3. This RSS file is also like a digital card catalog entry in that it points podcasting subscription software, aptly termed a podcatcher, to the mp3's position on the Net.