So, you see the light and set up your dual monitors in portrait orientation, rather than landscape. Then GNOME explodes, and you're stuck at a console trying to fix it with your neck rotated 90 degrees...
Never fear! fbcon to the rescue. fbcon is compiled into Fedora kernels, and happily, one of fbcon's abilities is that it can rotate consoles. So, add this to the kernel parameters in /etc/grub.conf:
it depends on which way you rotated your displays. Reboot, and rejoice as you no longer have to perform contortions to read your consoles.
You can adjust the setting on the fly by echoing the desired number to /sys/class/graphics/fbcon/rotate_all : this is a good way to test whether you need 1 or 3.