The best site to learn about creating DVD backups is without question
www.doom9.org. I would give second place to
http://forums.afterdawn.com/
In a nutshell you only need two pieces of software, dvd decryptor to remove the data from the original dvd and ifoedit which is used to strip elements of the dvd out in order to fit dual layered discs on single layer dvd-r's. The advanced stuff includes recompressing (downsampling) in order to fit all the dual layer goodies like outtakes and director'sc ommentary on a single layer backup discs.