I've been re-creating a stamp inventory database for my collection, and I've found this program to be very useful, so I thought I'd share for those who might have a similar need.
Bulk Rename UtilityIt's a program that allows you to do bulk renaming of files. It has enough options that you almost have to read the instructions (but of course, my chromosomes don't allow it).
Here's a screenshot from the website:

And best of all, it's free!