According to this page : http://docs.info.apple.com/article.html?path=Mac/10.5/en/cdb_sptfky.html
the keyboard shortcut to open the Spotlight menu in OS X is CMD-Space Bar.
However, I am using a japanese macbook pro. When I press CMD-Space Bar, the language input mode changes (switching between latin characters, japanese hiragana, japanese katakana).
How can I set the shortcut CMD-Space Bar to open the Spotlight menu ?