Although there isn’t a menu item to rename your presets in Adobe Camera Raw in Photoshop, you can simply rename them in the operating system. Your Camera Raw Presets are located here:
• Win (user)/Application Data/Adobe/Camera Raw/Settings
• Mac(user)/Library/Application Support/Adobe/Camera Raw/Settings
If you are on a Mac running Lion, the Library menu is hidden by default. To reveal it, hold the option key down while selecting the “Go” menu in the Finder.