I added a link to The Countdown with Keith Olbermann's Podcast.
If you click on the page link that is present on every entry, you can get the nightly broadcast in wmv format as well which means you can watch it on Windows Media Player (I personally hate Itunes).
It also has daily/weekly links to other shows like
Meet the Press
Nightly News with Brian Williams
The beauty of the feed is that it let's you know exactly when the show is available. The episodes get updated daily so if you miss it, you can't go back and get it the next day because it's gone.