Great suggestions, Andy.
Dawn,
What are you doing for your opening day?
If you've got a fun, special event, and you put that on your flyers, it'll make a bigger impression (and get more word-of-mouth/media coverage).
If you've got an open space nearby (like a small park), you could talk to the police and ask them if they'd do a police dog demonstration.
I happened to see one of these when I was on holiday in Paris a few years ago, and it drew a huge crowd.
(actually, I saw the crowd and went over to see what it was for)
It was a really impressive demo and it's good public relations for the police.
Alternatively, there are probably people in your area with trained dogs that do obstacle courses or tricks.
Something that involves animals that people would stop and watch, then give them a leaflet and send them off to your shop for free dog chews/cat sweets (or whatever).
Steve