First you need to make sure you have all the goodies that were not included in Ubuntu 10.04.
# sudo aptitude install ubuntu-restricted-extras
This will give you the codecs you need and some other goodies. Next you have to manually set up the ability to read DVDs.
# sudo /usr/share/doc/libdvdread4/install-css.sh
Now just pop in your DVD and you should be all set.
I am also working on my Things Ubuntu 10.04 Forgot Post. Look for it soon.