As you may know if you have purchased a new(er) copy of Microsoft Office, they introduced a new User Interface (UI) in Office 2007 called the Ribbon, and they mean it. They make no provision for going back to the menus of Office 2003.
This has lead to some controversy, many heated exchanges, and not a little name-calling. People used to the older interface accuse the designers of making change just for the sake of making change, and the designers in turn think that the people who want the old interface are stuck-in-the-mud Luddites, who cannot keep up with needed improvements. I don’t want to weigh in on this aspect of the controversy, other than to say that I can understand where each side is coming from to some degree. I think you get this any time you attempt to change an interface element. I am seeing it now in Ubuntu with the decision to move the window buttons from the right to the left.
The point that you might want to keep in mind here is that the change gives every appearance of being permanent, and I have heard that OpenOffice.org is considering making similar changes to their UI. So if you want to simply get on with it, to get some work done without fighting any major battles, I think there is merit in learning the new UI and making peace with it. And I can offer an interesting resource to help. One of the major designers maintains a blog on MSDN, and explains a lot of this. Unfortunately, finding things on that blog is not as easy as one might hope, so someone else published a guide with links to all of the pertinent posts. That guide is available here. By going here and reading the posts that Patrick Schmid has organized (from the blog of Jensen Harris), you can start with why they thought a change was necessary, learn about the philosophy of the new Ribbon UI, and details about how it works. This is highly recommended for getting up to speed.
Office 2007 Ribbon by Kevin O'Brien is licensed under a Creative Commons Attribution-ShareAlike 4.0 International License.