I am developing a SAAS application using MVC 3 and Windows Azure. I am developing in Visual Studio 2010.
As I will have a main website which promotes the product, what I want to be able to do is have my website and application separate. Would this be feasible to do it in the same solution and add as a separate project?
sure in Visual Studio 2010 you can have different projects in the same solution.
You can for example create a class library project for the Business Logic, another one for the Entities, a common one for the interfaces and another one for the data layer (with or without Entity Framework models…).
In the same solution you can then add a web application project which uses MVC 3 and C#.
In general for big projects you would have multiple solutions with many projects inside any of them. It depends really on the size of your whole architecture.
To decouple things nicely, you should imagine to communicate from MVC site to the business logic not via direct project reference but for example via web servives (XML or better WCF), so your business logic can be installed aferwards also on another machine than the web servers (for example an application server) and the web ui will just use a different machine name or ip address to direct all the WCF calls. we use this approach successfully in several projects.