From Add-in Express:
Add-in Express VCL is the first visual tool for writing a COM add-in, smart tag and RTD server in Delphi. It completely supports these technologies and makes them very comfortable for programming extensions for all available MicrosoftÃ??Ã?Â® Office versions from 2000 to the newest Microsoft Office 2007.
Visual designers: you write functional code only
Add-in Express VCL is entirely based on the Rapid Application Development approach and empowers you to develop professional plugins for Microsoft Office with a couple of clicks. The programming model and run-time code of Add-in Express are based on CodeGear VCL for Win32, written in Delphi and make your add-ins, smart tags, Microsoft Excel RTD servers and user-defined functions commercial class and feature-rich.
Add-in Express generates COM-based projects that comprise all necessary functionality for Microsoft Office add-ins or smart tags and centralize all technology-specific components through visual designers and RAD modules.