Podcasting is catching on as an extension of the blog. According to the Wikipedia, a podcast is like an audio magazine subscription: a subscriber receives regular audio programs delivered via the Internet, and can listen to them at their leisure.
Podcasts differ from traditional Internet audio in two important ways. In the past, listeners have had to either tune in to web radio on a schedule, or they have had to search for and download individual files from web pages. Podcasts are much easier to get. They can be listened to at any time because a copy is on the listener’s computer or portable music player (hence the "pod" in "podcasting"), and they are automatically delivered to subscribers, so no active downloading is required.
Using podcast technology, for instance, a podcasting program can automatically download new .mp3 files from your favorite blog. Of course, you can always just click on the .mp3 broadcast from your browser and listen to the podcast through your computer’s speakers.
So far, I know of three podcasting groups in the IP world so far:
Look for the inaugural Patently-O Podcast coming next month.
Aside: Since I am discussing blogging, I would recommend purchasing the newest version of Blogjet. It is great and integrates very nicely with Typepad.