Just in case someone have the same problem that I had.
After I update from FC4 to FC5 my keyboard was identified as US, but it's "Brazilian ABNT" but this layout is no longer avaliable at "Desktop > Preferences > Keyboard" so if you have the same problem, open the terminal and type:
Hit enter. Search for the Identifier "Keyboard0" and replace the 5 lines block by this:
Option "XkbModel" "abnt2"
Option "XkbLayout" "br"
Save it and do "Ctrl+Alc+Backspace" to restar your X server and it should be working now.