It has my website address on one side, and my name and mobile phone number on the other side.
The photo below shows the tag on the strap of my Canon 50D. It's securely attached, and is located so that it won't get in the way.

This is the smallest tag that they had available (22mm diameter), and coloured tags are also an option, as well as various assorted shapes. The coloured tags appear to be annodised aluminium, and the engraving would be a little more readable on the coloured tags, as it would expose the bright aluminium underneath the colour.
The tags are computer-engraved, and you can choose the font, as well as select a clip-art if desired. The cost was just AUD$11.95, and it took only a few minutes to enter my details into the computer and get it engraved.
Tagging your camera in this way ensures your contact details are permanently attached to the camera, and I hope anyone who ever finds my camera, if it goes missing, is honest enough to contact me ;-)
Another idea would be to engrave the camera/equipment itself.
The petshop probably hasn't got the right equipment for it, but more and more businesses do. Just ask around in your neighborhood. It will be a very permanent solution though, so be sure not to engrave in plastics ;-)