Flickr has a wizard to help you generate your own (unofficial) Flickr Photographer's Badge. Wear it whenever you venture into the urban wild with camera in hand. I plan to laminate and wear mine in one of my conference badge holders. You never know just how far it might get you!

Badge Maker: Create an Flickr ID badge using your digital photographs
Make your own (unofficial) Flickr badge. Print it out, laminate it, wear Flickr with pride! Show the world how truly photographically geeky you really are!

Once I generated my badge, I downloaded it locally as JPG, opened it in Photoshop CS2, added a layer to the image, and used a Graphire Tablet Pen to add my signature (due to security concerns, I have now replaced the image with a fake signature using a font). The final version was flattened as saved in JPG again. Someone has conveniently made a suitable backside of the Flickr Badge to give it that professional look!

See also:
The Photographer's Right
Your Rights When You Are Stopped or Confronted for Photography