I have just updated my Fedora 15 RC1 test installation with the latest Gnome 2.91.90 packages.
First is was struck by this error, but after downloading and installing some updated packages from Koji, I was up and running.
Here is some screenshots, There is a little special feature on my system, see if you can find it :)
[gallery link="file" columns="2" orderby="title"]
The button launcher is not part of Gnome3, it is docky :)