Best way is to create an action in photoshop which does it for you.  Just go to "file information" in the "file" menu and you will find all sorts of things in there which attach themselves to the exif which you can modify.  I have said action as part of my resize for web - it also puts a copyright symbol on it, so that if the file is opened up in photoshop or other image editing programs which suppport the feature, it will remind whoever is opening the image that it is indeed copyrighted as it will have the © next to the title in the title bar.

"In every colour, there's the light.
In every stone sleeps a crystal.
Remember the Shaman, when he used to say:
Man is the dream of the Dolphin"

Rich Meadows Photography