Lost Dogs and Loss Prevention:

GPS Tracking Devices for Dogs (note: this is a commercial, product-selling link, but Dog Friendship has no stake in the company and posted it because - unlike microchips - we had no idea these GPS devices were available and thought you might be interested)

Help with Finding Your Lost Dog

Paws with Heart - Check out these two website on how to avoid losing your dog - how to prepare in case you do - and how to search for them.

Ontario Humane Society Branches list (to find your local group) and this partial list of both humane socieites and non-humane-society rescues (you may also want to search the net)