MP3 audio files, iPods and Ham Radio
There are podcasts popping up everywhere, since the barriers to entry are low and it seems that everyone has something to say. The topics covered are all over the map, including music oriented programming and "talk radio" type programming. Many of these are targeted at specific interest groups. Not surprisingly, there are many technology-oriented podcasts, including This Week in Amateur Radio, a very impressive ham radio program.
You can play these podcasts on any modern PC, so you don't have to have an iPod or other mp3 players. Microsoft Windows comes standard with Windows Media Player and winamp is very popular mp3 player for Windows.