Seriously - wine buying needs to get much improved, and the G2/ iPhone 3GS could help with this.
Google has the tech to warp a distorted image to a straight image (used in their book scanning project, but a company could do something similar, as wine bottles pretty much have a simimlar shape where the label is, and they usually have straight edges, or at least the text is in horizontal lines...)
So what do you need?
Which shop? ID the location with the GPS / select supermarket, then a list of the supermarkets.
Which wines? Select what you want - price range, type (white red bubbly dessert)
Then the painful database bit - trying to display some wines the shop has. Now the supermarkets now this detail, but they won't likely let no what's on the shelves - but the churn isn't going to be that big - many supermarkets will have similar stock. Once the base stock for a small, medium and large supermarket is identified (crowd source!) then it's just updates to stock, and price changes/ offers.
Wish Gluck had been round for this kind of thing. Now this would be very mucheasier for supermarkets, but their concern is linking easily a review of a wine to their stock - it very easily identifies how good the wines they stock are, and also value for money.
In relation to http://en.wikipedia.org/wiki/The_Cluetrain_Manifesto -