How can I create class in specific folder (namespace) in my project, and see the classes grouped by there namespace?
When using Visual Studio Ultimate you can choose "Architecture" from the menu and generate a namespace diagram.
Once the diagram has rendered, you can expand the namespaces and other elements to show the classes they contain.
Note, specific folder != namespace. New files in given folders are defaulted to the namespace, but from experience, try not to rely on it when working in a team or with someone elses' code. ;-)