I followed the procedure at http://fedoraproject.org/wiki/YumUpgradeFaq so the point of this is just to go over my experience with these steps.

1. Review and remove all .rpmsave and .rpmnew files before and after upgrading
   I basically did a locate, found them and deleted them.
2. for a in $(find /etc /var -name ‘*.rpm?*’); do b=${a%.rpm?*}; diff -u $a $b; done
   I did this, but I didn’t really know what to do with the results. It appears not to have mattered in this case
3. yum clean all
4. rpm -Uvh http://mirror.anl.gov/pub/fedora/linux/releases/8/Everything/i386/os/Packages/fedora-release-8-3.noarch.rpm http://mirror.anl.gov/pub/fedora/linux/releases/8/Everything/i386/os/Packages/fedora-release-notes-8.0.0-3.noarch.rpm
5. v /etc/yum.repos.d/fedora-updates.repo.rpmnew /etc/yum.repos.d/fedora-updates.repo
   mv /etc/yum.repos.d/fedora.repo.rpmnew /etc/yum.repos.d/fedora.repo
   I tried this, but it appeared to be irrelevant as the .rpmnew file was not created. Got an error about the file not existing.
6. ctrl + alt + F1
7. telinit 3
8. yum update rpm\* yum\
9. yum upgrade
   This is the part that takes the longest, but I think it took just a few hours max. The dependencies were resolved within about a half hour and the rest of the time was downloading and installing
10. yum install yum-utils; package-cleanup –orphans
    I did this, but they were mostly packages I didn’t care about too much – mostly some emulators.
11. yum groupupdate Base
    In my case, this only updated/installed one or two packages

I then realized I had not had freshrpms enabled so I enabled it and yum update , but some of them failed; due to conflicts with livna, I presume.

12. yum groupinstall sound-and-video (if you are using Gnome)
13. rpm -e –noscripts avahi-0.6.17-1.fc7

And then I was updated and everything I’ve used so far on there appears to be working correctly.