'organize' is a command-line tool that creates organized directories
of photos and other media files. Photos can be easily organized by
metadata into a directory structure of your choosing. It is built on
Exiv2 and currently supports a fairly wide selection of exif, iptc,
and file metadata (xmp could be added if there is demand).

Please see the new Exiv2 forum for the full announcement:
http://dev.exiv2.org/boards/3/topics/show/44