you can use free software like dvd-decrypter to de-crypt all movie files onto hard disk and play it with windvd or powerdvd. you can use a dvd burning program to make images of dvd data.
than use alchohol 120%, virtual CD, deamon tools, or the one aye29 suggested to mount the image. you still have to have a dvd drive to make the images. you will not find too many dvd image online, they would be too massive. plus you are on 56k. each image is up to 8GB large
you can also use Dr.Divx or dvdx2.2 to compress the movie to mpeg3, mpeg4, or divx