Comment 4 for bug 384641

The tap to click touchpad settings in the gnome-settings-daemon mouse capplet only work when tap to click is already enabled right now. You can just do synclient TapButton1=1 (make a shortcut to it in a menu or start it with your session, or just type it for now...) to enable tapping. gnome-settings-daemon 2.27.4 will handle enabling/disabling tapping correctly when it is released.