There is a free way for you to do this:
Export your powerpoint slides to JPEG images, then use windows movie maker
to make a video, and then burn the video to DVD.
But in this way all the animations and transitions in your presentation will
be lost.
So far the best way i know is to convert your PowerPoint presentation to
MPEG-2 video format first, then burn the video to DVD.
You can have a try at this tool:
http://www.ppt-to-video.com/powerpoint-to-video-overview.html#105
It helps you easily convert your powerpoint presentation to MPEG-2 video
format. All things in the original PowerPoint will be retained.
If you still want to create DVD menus for your presentation to be viewed on
TV with a remote control.
You can have a try at this tool, a professional PowerPoint to DVD tool.
http://www.ppt-to-video.com/powerpoint-to-dvd-overview.html#105
It can help you burn your PowerPoint directly to DVD.
You can get the free version of them through:
http://www.ppt-to-video.com/powerpoint-to-dvd-download.html#105
Hope it can help