There are not a lot of free software options for mastering DVDs. One of the more complete solutions is QDVDAuthor, although it still has a number of rough spots. It's a front-end to a collection of command-line free software tools that do each of the individual steps involved in going from a collection of digital video files, audio files, and images to a DVD with menus. As such, it's quite complicated, and not as stable as some software. Still, it is a rewarding experience if you stick with it. Here I'm going to walk through creating a DVD for a collection of animated videos by my new favorite free-culture artist, Nina Paley (partly because the CC By-SA 3.0 license eliminates any questions about copying the material here, and partly because they're pretty cool in themselves).