There are paid softwares control kits available for .NET framework which would provide you the same look and feel as of Office 2007.
In case you interested in free Ribbon control, would suggest you register at microsoft site for visual studio express edition and you would be given a free link for Telerik ribbon control which you can use in your application.
Remember that Office 2007 UI is licensed by microsoft and hence you need to follow certian guidelines before you make a commerical application. The link will be useful to get an idea about UI licensing.
http://msdn.microsoft.com/hi-in/office/aa973809(en-us).aspx
Kavitesh Singh.