I found these great dog tags and thought ya'll might want to check them out.
My favorite is a sliding tag that goes on the collar, it's just the perfect size for our small babies. Go Tags
It's stainless steel, about 1/2" wide and 1 1/2" long, and fits perfectly on Chicos nylon braided collar. The engraving is in black and although it's small, his name and our full address is readable. I can't get him to sit still long enough for a decent photo but I'll try later.
The others are colorful aluminum in different shapes that are lasar engraved. I found these on eBay and got 5 for $10. Lasar Dog Tags
. I got different sizes for things like his leash, his carrier, etc. plus a couple of real small ones that wouldn't be too big for his collar. I bought these first before I found the sliding one but they'll get used, too.