Video How to: Calling Code in an Application-Level Add-in from VBA
You can expose an object in an application-level add-in to other Microsoft Office solutions, including Visual Basic for Applications (VBA) solutions and COM add-ins.
This video shows you how to write a method in an add-in for Microsoft Office Excel 2007 that you can call from VBA code in the workbook. The following tasks are included in the process:
Defining a class that can be exposed to other Office solutions.
Exposing the class to other Office solutions.
Calling a method of the class from VBA code.
The Visual Studio Tools for Office Help includes the code and the steps that are demonstrated in this video. See Walkthrough: Calling Code in an Application-Level Add-in from VBA.