Depends on what you need to do to the DVD. Ultra ISO can "Replicate" the entire dvd to HD which you can then mount as a "Virtual" DVD to play it with normal software WITHOUT COMPRESSION. Works on copy protected DVD's as well.
If you have one of those nice little passport WD external USB drives (320GB) you can copy around 75 - 80 entire DVD's to one of these devices.
Otherwise copy it with some DIVX decoder -- a lot of "Ordinary" DVD players will play DIVX so you don't have to watch the DVD on a computer.
This stuff USED to be free -- however some of these sites are getting very sneaky -- they often say FREE DOWNLOAD but sometimes the actual SOFTWARE isn't free.
Legal threats have deterred some of the larger software companies from distributing DVD ripping software. Thus the only software you will find will be from companies you may not have heard of. Do an online search on "DVD ripping software" for a list of options. Compare different products, read any disclosures carefully, and look for non-biased reviews (5 best dvd ripper review comparisons) on the products to decide on the right product for yourself.