Susan Pinochet

Susan Pinochet at

My wife wants to become an Excel ninja. (It is for her job; we use free software at home.) Her preferred learning mode is self-help books. Can anyone recommend a good one for this purpose? She currently has 2006, but may upgrade when they get off of XP. Are the differences large enough that the version will matter? I know nothing of Excel, so any guidance anyone can give would be most helpful., shared this.