Shamelessly lifted from BeyondTV forum:
http://forums.snapstream.com/vb/showthread.php?t=22432&highlight=dvdauthor
Takes a DVD-compliant MPEG2 video file and burns it to a DVD, formatted so that it plays in a standard DVD player. Once you set it up, one command-line call does the whole process. Takes about 20 minutes on my 2GHz P4 to a DVD-RW. Add a "execute command" button to your skin and start burning away.
Requires Nero, but the rest is freeware and included in the package. Also, I suppose if your source isn't MPEG2 you could add a conversion step using Nero Recode--I don't need that step since my source is a Hauppauge PVR-500 capture card.
Editorial comment: Great for sharing shows with friends or playing on the portable DVD in the car/airplane. I'm using this is my alternative until the price of those "Portable Media Centers" come down.