Excel 2007 was a big change from Excel 2003 in that it uses the Ribbon rather than the menus that we had all been so used to for so many years. With Excel 2010 there were some more changes and tidied up a lot of what had been done in 2007 and added new features.
If you were using Excel 2003 and moved to 2007 or 2010 then this video will help you even though it is specifically for those moving from 2003 to 2010.
Gary Schwartz's Blog 