Hell, if they wanted to use a free streaming server then they could easily use
QuickTime Streaming Server (runs on OS X) or
Darwin Streaming Server (runs on OS X, Red Hat Linux 9, Solaris 9, Windows 2000 Server or Windows 2003 Server) and stream everything in MPEG4. It even does 3GPP streaming for mobile phones, which would be a nice addition to their existing services.
There are more than enough options for client software that way (I know that at the very least QuickTime Player and RealOne Player/Realplayer can handle MPEG4 and I'm sure there must be options for WMP to handle it as well).