We are terribly sorry that you have lost your pet and we know how stressfull it can be. This lost and found forum on Pets.ca is VERY popular so of course post your information for free here in this forum.
Here's what else you can do
Go out to look for your dog or cat early in the morning/dawn (when it's quiet out), with a box of its favourite treats. Make sure to bring a leash & collar.
Distribute "Lost Dog" flyers, with a recent picture, in your neighbourhood: poles, alleys, veterinary clinics, convenience stores, grocery stores, pet shops, and other internet sites.
Hopefully your pet had a pet tag or some other form of pet identification. If it didn't, when you find your pet make that the FIRST thing you do after a good hugging. More info. on Pet identification can be found at http://www.pets.ca/pettips/tips-64.htm
There are other sites that are good to get the word out and they are listed below. All someone would have to do is make a detailed statement and then cut and paste into the database of each website. Please ALWAYS remember to list your city and immediate surroundings where the pet was lost AND provide a picture whenever possible.
*this is INTERNATIONAL
Mostly Ontario Canada
The bottom 2 are particularly good for Montreal Quebec Canada
9825 Henri Bourassa East
Jean Talon SPCA Montreal
5215 Jean Talon Ouest
Thanks especially to Luba and Badger for helping with this thread.