Using the msbuild community tasks project it becomes easy to change App.config and Web.config files as part of the build process. I've recently implemented a build script for a smart client application that allows building in multiple locations connecting to different application servers. First, download the msbuild community tasks project. You can get this from subversion using the following command: svn checkout http://msbuildtasks.tigris.... msbuildtasks --username guest ......