on the pages of Fraunhofer Institute you can download a evaluation software for mp3 surround. It demonstrate the MP3 Surround technology. No surround players will use a mp3 compatible stereo downmix.
How can I playback an MP3 Surround file on PC?
You can play back an MP3 Surround file on any existing MP3 player or device in excellent stereo quality. In order to enjoy the full surround experience on a PC, your computer needs to be equipped with a 5.1 surround sound card (USB or PCI) and speakers. You also need the MP3 Surround decoder software installed on your PC.
The license fees you can read here http://www.mp3licensing.com/
(seems page isn't updated yet)