Because I wanted to use a smart folder to show me photos taken in the last 6 months in my picasa library, I needed to make sure the on disk created attribute matched. Unfortunately it didn't, so I needed to make something to do this.
It didn't seem possible with unix tools, because they dont't have access to the HFS/ Mac specific created metadata. So some googling found a tool that would let me do this, which I've included here as well as a ruby script to read the exif data and call this command