One for us digital camera owners out there: ARen 1.06 (via the ever wonderful Lockergnome newsletter).
As the website says (as written by the Danish author): “You just add a lot of files to a list, and then choose how they should be renamed. Then you start the program and then you have a big bunch of files correctly renamed. This program can rename in many ways, including mp3 tag renaming. The days of renaming every single little file is now over. With this program you can rename alot of files in a snap. Ideal for pictures, musik and small video files.”
