I saw a similar post here and I'm unfortunately in the same position. I've accidentally removed the gnome-power-manager icon from my panel. The solution posted was to go to:
System --> Preferences --> More Preferences --> Power Management
I opened the power management and switched the Notification Area to "always display icon" but the icon does not show up.
I'm running fc6. Any ideas how to get the icon back? Sorry for a rather lame first post... haha.