"Fraunhofer Institute for Integrated Circuits IIS, inventors of mp3, together with Thomson, co-inventors of mp3 and exclusive licensing representative for their mp3 patents and software, and Agere Systems, have joined to launch mp3 SURROUND into the consumer and commercial markets. This technology will enable 5.1 channels surround-quality sound for a broad spectrum of applications including web-based music distribution, broadcasting systems, PC-related audiovisual or gaming applications, consumer electronics and automotive systems."
I guess this is good news, but honestly I don't see much application for end users. I would suspect that in the future, surround sound audio files will be wrapped in DRM, thus being either WMA or AAC. Maybe games and other software packages will use it, but this late in the game no one is going use MP3 5.1.