Prior Fedora installations are described in later sections.
This was my easiest upgrade ever. Around mid-June 2009, an alert popped up inviting me to upgrade, and I bit. After the upgrade, everything appears to work! Amazing!
I did have one headbutt, however: my /boot partition filled up during the upgrade, causing it to fail. To fix that, I rebooted in single-user mode, deleted all old kernels lying around, and reran /usr/sbin/preupgrade-gtk.py. (After the upgrade, this file was gone, so I would now try /usr/sbin/preupgrade.) The upgrade process installed itself as a bootable kernel, and I had to manually choose it at start-up before the time-out since the default kernel choice was a Fedora 10 kernel.