Digimarc (http://www.digimarc.com provides a free digital "watermark" & comes packaged with PSP & PS. They give you a unique ID number & will let you display your contact info for potential customers once you register. You can, for extra $$$, even add enhancements which will allow you to track your pics on the web, if necessary. Additonally once a graphic is watermarked it cannot be overwritten, at least not a digimarc. I tried once on a misdated piece I did & got an error msg "There is already a registered watermark present" :-)