I use DVD Decrypter to rip : http://www.dvddecrypter.com/
You can simply rip and feed the VOB files to something like DVD2AVI : http://arbor.ee.ntu.edu.tw/~jackei/dvd2avi/
This can take care of the conversion to wav if you play with the audio
settings.
Alternatively, you can demux the AC3 audio files while in DVD
Decrypter, using stream processing, then convert them to wavs using a
program like Foobar 2000 : http://www.foobar2000.org/
There is probably a simpler way, but there you go.
Head over to www.doom9.org and goto the download page Audio
section. Get Besweet and Besweet GUI. Put them in a folder
and click Besweet gui.
Select the path for besweet.exe and then for the VOB or AC3
file you wish to create the waves from (you may have to rip
from dvd first use DVD decrypter also on the download page)
use the drop down box for desired format and double click
the desired file for confimation of choice.
a little trial and error and voila
check out the guides also at doom9