Liquor Locator iPhone app
You can find an analogue here on their site — it’s just like any other store locator app, but it’s by brand. The same will apply to the iPhone app (which I’ve mocked up to the right, pretty nicely too). So if you need a fifth of Three Olives on your person at all times and no other will do, this is probably going to be your thing.
Somebody needs to make an iPhone app out there that allows you to choose from more than their own brands of liquors — companies would pay good money to have their names included on a default list.