Microsoft has just launched Office 2010 and a free trial download is available at here. This version has many new features such as an intuitive navigation, better copy paste options, inline photo editing option, etc.
However, many people who switch directly from the 2003 version to the 2010 version find a bit difficult to use menu and commands, as many tools and functions are reorganized and moved to a different menu.
Or, you can download and use the Office 2010 reference workbooks created by Microsoft. They’re available as Excel documents (XLSX) and included all the command equivalences between the 2003 and the 2010 Office versions.