Rename It is a free Explorer shell extension that can easily change the extensions of one or more files. It can also rename a series of files in one operation, such as image01.jpg, image02.jpg, image03.jpg, etc. Just right-click on highlighted files in an Explorer window and choose one of the Rename It menu options. A stand-alone executable is also included for renaming groups of files from other applications that don't use the Windows context menus but have their own Explorer-type interface (such as ACDSee). Every rename operation can be undone from within Explorer.
