Load a 6-channel WAV file into ffmpegX and select the .AC3 output setting, and you''ll get a 5.1 audio file you can burn to DVD.
There are many ways to distribute your music in 5.1-channel surround. But encoding it in Dolby Digital (AC-3) format will accommodate the most listeners, because all DVD players support AC-3. There are numerous AC-3 encoders online. You simply feed them six mono 16-bit, 48 kHz WAV files or an interleaved 6-channel WAV file and click on a button. Then you load the resulting AC-3 into a DVD-burning program, create some menus, and burn a disc. (I burn a disc image while testing.)
On the Mac, you can make surround DVDs with Roxio Toast (roxio.com; $79.99), but there's a secret: to import an AC-3 file, you have to Option-drag it onto the Toast window. In Windows, try Audio DVD Creator (audio-dvd-creator.com; $39.95). For AC-3 encoding on the Mac, I use De-Interleaver (scottwilson.ca; free) followed by ffmpegX (ffmpegx.com; $15), with WAVs arranged in L, C, R, Ls, Rs, LFE order. (For more about David Battino's work, visit batmosphere.com.)