I never had a real need to watch DVD's on a computer - so DVD playback was not something I needed to get working with Fedora. Recently however, the need arose and to my surprise, the amount of information on the internet about Linux DVD playback is very out-of-date. libdvdcss - the library required to decrypt DVD content is not distributed by any of the usual repositories due to the licensing/legal restrictions (In the US, using libdvdcss may be considered as a DMCA violation. Whoever comes up with these ridiculous laws in the "land of the free" anyway?) The only repository carrying it was livna - which has sadly disappeared off the internet.
Luckily, ATrpm's is still maintaining an up-to-date list of packages and I found the F13 x86_64 version through pbone at http://rpm.pbone.net/index.php3/stat/4/idpl/14089850/dir/fedora_13/com/libdvdcss2-1.2.10-5.fc13.x86_64.rpm.html.
Install is a breeze with:
sudo yum --nogpgcheck localinstall libdvdcss2-1.2.10-5.fc13.x86_64.rpm
Now DVD's work flawlessly with Totem.