I, I mean you, can use DVD Decrypter to rip the movie, copy it from the DVD to your hard drive removing copy protection. If you do not have Nero DVD Decrypter will burn the new DVD also.
Then use DVD Shrink to remove previews and other content you do not need or want like French subtitles. It allows you to shrink the movie down, if necessary to fit on a 4.7GB DVD. Some movies are actually on a 8GB dual layer DVD. My DVD burns dual layer but the media is not generally available or cheap. You can buy 50 8X DVD's for $25 on sale at Best Buy, Circuit City and other places.
It can take up to 45 minutes to rip a DVD and 6-12 minutes to burn depending on your processor and DVD speed.
BIATCH gave you a good site, google DVD ripping or copying, there are a lot of others. Remember the DMA says this is illegal. So is speeding, use your best judgement.