Visual Studio Tools for the Office system (3.0) is the key developer technology that enables you to create scalable, LOB solutions for Microsoft Office by using the Office development features included with Visual Studio 2008.
Steve Fox and I thought it would be a great idea to write an article that talks about the evolution of Visual Studio Tools for Microsoft Office and Office Development, how it all relates to Office Business Applications, the different business productivity solutions you can build using VSTO, and a brief overview of the rich set of features with which to build and deploy customized Office Business Applications using VSTO. We also provided links to resources that provide a deep dive to each feature.
The figure below shows the benefits of VSTO 3.0:
I really recommend reading our article. It is a good resource that will help you get started with Office development in Visual Studio 2008.
Also, if you are looking for detailed code samples, videos, and articles related to VSTO 3.0, please explore our MSDN technical articles, Visual How Tos, and reference documentation. Of course. the VSTO team blog is a must see.