I created an empty \'Demo\' project in Visual Studio 2008 and added some existing projects to my solution. Included \"MyHeader.h\" (other project\'s header) in main.cpp file
If you choose Project and then All Files in the menu, all files should be displayed in the Solution Explorer that are physically in your project map, but not (yet) included in your project. If you right click on the file you want to add in the Solution Explorer, you can include it.