Mac Utility - Name Mangler
Just found out about Name Mangler from a friend last night. Its a super useful and super easy utility for mass renaming of files. From the site
If you need to rename several files at once every now and then, this is the application you have always been looking for. Name Mangler is a batch file renamer that supports all common renaming tasks: Find and Replace (including support for regular expressions); Number Sequentially; Change Case; Set Extension; Add Prefix/Suffix; Remove/Insert Characters.
Here is a screenshot:
