Recently at the verizon store, I saw a device for your dog that allows him to use GPS and texting. The advertisement was something like a picture of a dog in a park with a thing on his collar, and his owner getting a text that says "At the park!" I was like "waaaaat?"
Apparently, it's kind of like a microchip, except not. If your dog is lost, you can have a GPS signal sent to your phone to find him, and if he ends up somewhere like a vet's office or something, the device will text you to tell you where he is.