If you are distributing prerecorded audio content online for people to listen to, you need to distribute MP3 files. End of story. Not any of the myriads of protected formats like Real, various flash-based players, etc.
When I want to listen to internet content, I want to download it and listen to it later, usually while driving home from the office. And many people like to listen to audio programs on their iPods or other MP3 players. The protected / streaming formats do not allow this.
I consider seeing a site with audio content where MP3 files are not provided as evidence that that site is completely clueless about how people wish to use the internet. For a media organization like Wisconsin Public Radio to offend in this manner is simply beyond acceptable.
Get with the program, folks!