How to create a shared ASP.Net MVC project (web framework) so that it can be re-used in other multiple MVC projects ?

Create your MVC project as normal then add your shared project as a class library to the same solution and add a Project Reference to the shared project from your MVC project. For other sites add the same shared library to those solutions also. That way if you need to make changes to the shared library you can make them right away, and every time you open a different solution you'll automatically get the latest version of the shared project too. Obviously you have to be wary of breaking changes though, ie changes to the shared library that might break other projects. As this method will give you different versions of the dll with the project you're only sharing the source code really, each project will have its own copy of the assembly. To actually share the assembly itself you'll need to use the GAC but that'll be more hassle than is worth and gives you a far greater risk of updates breaking other projects.