If you want to extract a particular angle, get a hold of a copy of SmartRipper. With the DVD in the drive, run the program and when it's finished loading, it should show the movie's program chain expanded to show all the angles. Select the angle you want to work with, and in the adjacent pane, select the chapter or chapters you want to extract. Click on stream processing and select which streams you want extracted. Also there, you can choose whether to copy the streams to a new VOB, or extract them to the mpeg and ac3 files.