DVDStyler is a cross-platform, free DVD authoring application.

It creates DVDs that can be played on almost any standalone DVD player. You can design interactive DVD menus and the interface is simple and intuitive to use.

If you do run into problems with image quality or opening different video formats, then try using a different application (like Avidemux) to transcode your video into DVD-ready MPEG-2 files, and then import them to DVDStyler.

Creating a DVD of key campaign videos as part of a film screening pack to be sent out to your networks

By far the best free software application for creating DVDs

DVD creation is a tricky process so it is hard for DVDStyler to compete against commercial applications
Has problems with some video formats

Windows, Mac OSX, Linux - http://www.dvdstyler.org/en/downloads

DVDStudio, iDVD, Adobe Encore, http://www.dvdflick.net/