Batch Rename is a free Automator action that will allow you to batch change the names of the Finder items passed into it.

Batch Rename works best as a Contextual Menu Plug-in; copy into ~/Library/Workflows/Applications/Finder/. It will also work well as an Application for drag-and-drop use.

Batch Rename will allow you to modify the name of your files or folders by adding date and time, adding text, change the case, make them sequential, or replace it altogether.