Ok, so podcasting is really catching on. My friend David started one, Music of the Third Millennium. If you are a composer type, you should submit a piece to it! And everyone should listen. You may wonder how to do that. With itunes: Get the latest copy of itunes from Apple or via software update. Under The "Advanced" Menu, select "Subscribe to podcast." A window will open, demanding a URL. Put in: http://euplastic.com/podcast/?feed=rss2. Violà! You're subscribed.
You can find other podcasts through the podcast directory. Click on the "Podcasts" icon on the menu on the left. At bottom of itunes, you will see some text "podcast directory." click on that. Once you are in the podcast directory, you can search for things like "experimental music," but this is very new, so you won't find much.
Later: how to start your own podcast AND Qu'est-ce que c'est podcasts? en français