The Society has been getting a number of emails from people who have lost their cats in the last few days. The first thing you should do is call the AVA and SPCA to check if they have your cat - and ask your neighbours.
I attended a talk by a woman, Kat Albrecht, who tracks pets down which have gone missing while I was at CHAMP. What was interesting is that she mentioned that cats that have been missing for a longer time are not necessarily gone. In fact, she mentioned that some cats will not come out for several days even if the owner is calling for the cat. She said it depends very much on the personality of the cat. This works much better for indoor only cats though.
Check out these links :-
Lost a Pet
Cats In the Bag
Of course the best way to make sure your cat doesn't go missing is to remember to keep them safely indoors.