Many of my friends recently asked me about GAC and the Side by Side Versioning support .Net provides. After doing a lot of R&D, one of them came up with a question like this : How to use two different versions of an assembly by using a GAC. He knew how to add Assemblies to GAC so that was not at all a problem, infact, if you refer to HOW TO: Install an Assembly into the Global Assembly Cache in Visual Studio .NET its pretty simple. However, after you add it to GAC, the .Net IDE doesnt show you those assemblies, listed in Add Reference Dialog Box.
After searching MS KB, I got an easy way to do that, here it follows :
Open Registry Editor and add the following Key to it.
Here, ESSAssemblies is the name of the Folder where your Assemblies reside.