I seem to have the same problem with every new Fedora/Gnome release
I run Maya which needs the Alt key to pan around the viewport. But the default gnome setting is for the alt+lmb to move the physical window around the desktop.
Previously, with Fedora16, I changed the mouse_button_modifier in gconf-editor (apps - metacity) - I usually swap it with <Super>
But metacity no longer appears in gconf-editor in Fedora 17.
Itś pretty critical for my apps to have Alt key back, if anyone can help I would very much appreciate it.