is it a commercial dvd (one you can buy in the store) or is it a dvd somebody burned with his DVD-Recorder directly from TV?
if it's a commercial dvd, it's propably protected by CSS. While it's no problem to work around that protection, it's not legal anymore in the EU (even if you do own the DVD and want to rip it for presonal use...). It's not hard to do, but since it's borderline legal even outside the EU I won't name it here
if it's burnt by some home DVD-Recorder it should be pretty easy, since DVD-Video stores the data already in Mpeg2-format. I'll have to check at home first to see which files to extract exactly. There's a lot of tools available that do exactly do that, but I can't name them since, most of them do "other" stuff as well
for the editing i'd suggest you have a look at
VirtualDub which is free, and allows to easily edit mpeg-files. It's of course not as powerfull as Adobe Premiere, for example, but it's free