You own a digital camera and use Mac OS X? Well, if so, check out ExifRenamer. Basically, it's a drag and drop application that renames your digital photos using the date and time that each photo was taken. In the Finder, this allows you to easily sort your photos chronologically and see the actual date and time each photo was taken — without having to open the file. ExifRenamer gets the date and time information from the EXIF data that is stored within each digital photo by digital cameras.
As an example, it renamed a photo named "839-3920_IMG.JPG" to "20020814-075018pm.JPG". So this photo was taken on August 14, 2002 at 18 seconds past 7:50pm! ExifRenamer is speedy and its naming format is highly customizable too.
The author, Stefan Robl of Germany, very politely asks for a donation if you like the program. I'm certainly donating!