I assume that you want to keep the video in its native quality, which would mean about 18 minutes per single layer disc if you're working with DV video.
Open the project file, create a new Sequence and place the clips on the Timeline. Set an IN point at the beginning and an OUT point at the 18 minute mark. Export a self contained QuickTime Movie at current settings (do not recompress) and then burn the resulting file to disc as a "data DVD." Repeat as needed.
That said, DVD isn't the best archiving media. It would be better to simply keep the original tapes.
-DH