When creating a project in Xcode 4, it asks what Class prefix to add to all new files.
Is there a way to change (or remove) this, after a project is already started?
In Xcode 4.3 at least it is persistent. To change it click on your project then in the right hand menu there is an option to change it. If you don't have the right hand menu open hit the button up at the top to make it appear.