You might have noticed that when you open System Preferences > International > Input Menu, there is no Character Palette or Keyboard Viewer.
This can easily be fixed by deleting some cache files with either a “payload-free” package and a postinstall script, or on first boot i.e. launching a script using a Launch Daemon.
Apple posted a solution to this problem on July 15th, 2008. These are the two lines of code you need:
/bin/rm /System/Library/Caches/com.apple.IntlDataCache*
/bin/rm /var/folders/*/*/-Caches-/com.apple.IntlDataCache*
Mac OS X Leopard: Keyboard Viewer, Character Palette does not appear
http://support.apple.com/kb/TS1896
Edit: I just noticed that Patrick Fergus posted a similar thread back in april 2008.