Renaming projects in Xcode 4
Well, it turned out to be a trivial matter indeed.
All you need to do is click twice slowly on the project root in the project navigator and it then becomes editable. After you rename the project and press 'enter' it will suggest to automatically change all project-name-related entries and will allow you to de-select some of them if you want.
Nice.
Another option - Move the cursor on project name. Hit Enter. The project name becomes editable.