There are free decrypter programs
that enable you to rip dvd's to your hard drive, BUT
... They are not legal. DVD's are usually copy protected, and this requires stripping the copy protection away so that it can be copied to hdd. The only way to save a "legal" copy of a dvd to your hard drive is to save the "digital copy" of it that is included with the dvd. If no digital copy is included, then you can download one from sites such as CinemaNow
and blockbuster, but this entails re-purchasing the download copy.