I’ve talked before about the Interactive Guides on where to find a command in Office 2007, if you know where it was in 2003. The links still work, but meanwhile Microsoft has put them all on one page.
You not only get links to the Interactive Guides for Access, Excel, Word, PowerPoint and Outlook, you can also download them.
Also, on that same page, you’ll find links to Mapping Workbooks, which are Excel Workbooks that contain lists of all Office 2003 menu and toolbar commands and their locations in the 2007 Office system.