Excel 2012 and earlier versions did not include native support for accessing web services directly. However, there are several easy methods
available to access the web services. We have included links to articles detailing connectivity with earlier versions of Excel.
Click on any of the articles below to learn more about webservice connectivity with Excel 2012 and earlier versions
Consuming Web Service from Excel
MSDN Article - Consuming Web Services in Excel 2007
Microsoft Dev Center - How to call web service in Excel using VSTO