Mark, if you still have the original tapes of the video I would suggest you use these rather than try and pull video off a DVD. There is a lot of compression involved in encoding a DVD (MPEG2) and pulling video off the DVD will result in quite a bit of loss in quality.
If you are running XP, Vista, or Win 7 on a PC you should have Windows Movie Maker bundled in the operating system. You will not need any other hard ware or software to capture video from your cam other than a firewire or USB cable.
If you have a firewire port use it rather than a USB port. USB can be slow and unreliable for moving video. You will need a firewire cable, 4 pin to 6 pin.
Open Windows Movie Maker and you will see an option "capture from video device". Be sure to connect your cable to both your cam and PC BEFORE turning your PC on as there is the possibility of frying the firewire port on your cam if you connect it to a hot PC. With your cam connected to PC with firewire cable put your cam in VTR mode, turn on, and click "capture from video device" in Movie Maker. Once your video is loaded into Movie Maker you can do some basic editing with the program and then will be given several export options depending on what you want to do with the video.
If you're running a Mac I believe iMovie is bundled in that operating system and will do basically the same thing.