Yes. VOB files are essentially MPEG2 encoded video. Something like TMPGenc will do the conversion.
Howver, I would suggest you first try simply changing the extension to .mpg from .vob (assuming they are not encrypted this should work). Alternatively transcode to DV as described in the FAQ (as MPEG editing isn't recommended):
http://www.videoforums.co.uk/reviews/faq
If they are encrypted, you'll need to download DVD Decrypter