We bought tags from
Pet ID Tags, Dog Tags, Collars, Leashes! . They are durable, have lots of choices, and for $9.95 you can register yourself as the owner.
For that one time fee, they keep a record on all your pets that have their tag, now and in the future. Anyone that finds the dog will have your info on the tag, plus a 1-800 number they can call. You can put many numbers on your registration -- your land line, cell phones, vets number, friends numbers ... so if something happens luckypet will contact every number to be sure the pet gets the help they need ASAP.