I second DVD decryptor or DVD shrink, both free. DVD shrink is a bit easier to use. The output will either be saved in an iso format or if they are saved in AUDIO_TS & VIDEO_TS folders you can just copy the folders as is to the DVD and you are set.
very simple stuff. If you are using single layer DVD's you are going to need to use DVD shrink for almost all of them to fit them on one dvd (they need to be recompressed).
A simple search will get you download links.
DVD shrink does have its problems decoding some DVDs though...listed at the link below, there are tips there on how to overcome them (it is 3 pages, with the 2nd page showing you how to use DVD-cryptor to overcome those problems)
www.dvdr-digest.com/articles/article_dvdshrink_problem_page1.htmlJust use the software that you got with your burner to write the DVD's, no need to buy additional software. I personally have given up on the backup business I just have a really big hard drive where I just store the iso's of all my DVD's on and just use Daemon tools (an old version (pre 4.0) the new version sucks) and just mount the discs virtually essentially giving me a ~50 disc dvd server. It is more expensive that way, but it is soo much nicer making for one cool HTPC.