Promising to "Play the web", Songbird is a new music programme that, amongst other things, can scrape a website or blog to gather up all the audio files. Based on the open-source code base that Firefox uses, not only will Songbird index all the music on your PC (making it an alternative to WMP or iTunes), but it can do the same for Wikipedia, Audioscrobbler and any url you choose to examine.
Once it has assessed a site, you can then instruct it to monitor for any new files added and automatically download them. Think of it as a combined audio player and podcasting manager, only you don't necessarily need to download a file to play it - Songbird can create m3u playlists on-the-fly to stream any number of audio files from a site.
A free download, Songbird's architecture lends itself well to custom code in a way that iTunes and WMP developers struggle with - think lots and lots of Firefox extensions on the way.