Mickey over at Mastering Emacs has a nice post on wdired. Dired is an underappreciated part of Emacs but even many who use it don’t realize that you can edit file names, permissions, and owner/group directly in the dired buffer and have the changes reflected in the file system. That ability is already built-in. All you need to do is toggle it on with 【Ctrl+x Ctrl+q】 and make your changes. See Mickey’s post for the details.
If you want to see it in action, watch Magnar Sveen use it to change the names of several files at once using wdired and multiple cursors.