Is there anyway to take the video off of a DVD I made with Vegas Video that is on the DVD in mpeg back off, import it back into the Vegas Timeline to edit it?
The feature was added in Vegas 6.0c. If you do a search for "VOB" you'll get lots of info on doing it in previous versions and many workarounds to the problems involved. Personally, in previous versions I found it easier to just hook the DVD player to my camera/convertor/deck and then recapture via firewire as DV-AVI. MPEG is not a good editing format.
The file that is on your DVD is not an .AVI file anyway. Capturing as Edward suggests will give you far better results than editing and re-rendering the MPEG file that is on the DVD!
No matter what you do the quality won't be as good as the original DV-AVI file. You've already compressed it to MPEG2 to get it onto the DVD! If you want the original DV-AVI quality, recapture from the original tape. When I finish my edits, I not only make a DVD but also output to MiniDV as well. Then if I need to edit from that edit, I can just capture from the master tape I created.