Irena Kennedy has a WPF ApplicationCommands sample on her blog. The sample is very simple but shows how to hook cut/copy/paste/undo/redo commands for a textbox in WPF. However, there are some minor issues. The sample explicitly sets the command target which prevents each of the commands from targeting the control that has focus. A better approach is to add each of the commands to a toolbar or menu:
<MenuItem Command="ApplicationCommands.Cut" />
<MenuItem Command="ApplicationCommands.Copy" />
<MenuItem Command="ApplicationCommands.Paste" />
<MenuItem Command="ApplicationCommands.Undo" />
<MenuItem Command="ApplicationCommands.Redo" />
Menus have native support for ICommand.CanExecuteChanged so the MenuItems correctly reflect ICommand.CanExecute using Control.Enabled.
Have a look at the Commanding Overview in the MSDN for more detailed information.