I second www.doom9.org and Gordian Knot. Once you figure it out it works wonders. Apparently there is now an AutoGK (automated gordian knot) package also available, although I haven't tried it. If it works well, that's the way to go for sure.
If you're interested in making backup copies of DVDs, DVD Decrypter and DVD Shrink (both free) work very well. (of course, you'll have to have a DVD writer
)
PS making VOB files into another format isn't illegal unless whatever it is is copyrighted. And even if it is copyrighted, you're allowed to make a backup copy of your own stuff.
