It's available for Mac, Windows, and Linux; if you're on Debian unstable the installation is as simple as
apt-get install democracyplayer (I uploaded the new packages yesterday, they should have reached all mirrors by now).
If you want to know what this is all about, but you're reluctant to install yet another program, check out this screencast (MOV, 37MB) which shows the basic functionality and user interface and discusses some of the new features... I think you'll like it.
You can use it for all kinds of video blogs and podcasts, it'll download and play almost anything with an RSS feed.