VS2008 Professinal has wizards that automate the process to create the add-in project and the windows installer/ click once deployment if required. Furthermore it uses a technology called VSTO version 3.0 that it is only available for the professinal edition.
http://en.wikipedia.org/wiki/Visual_Studio_Tools_for_Officehttp://msdn.microsoft.com/en-us/vsto/default.aspxNote: Your link is about implementing using COM which is far more difficult/time consuming