For most of ERP vendors, one of the areas which makes the solution stands out is the usability. The application which provides the intuitive navigation and the seamless integration with information worker’s daily job, wins the competition. I could not agree more on it. iPhone concept does work for ERP software.
Approva’s integration with Mircosoft Office is a good case study of Office Business Application (OBA) as it puts. You can see how it integrates with Microsoft portal, Outlook and Excel.
http://www.microsoft.com/casestudies/casestudy.aspx?casestudyid=4000000530