Back in July this year, I wrote a short scribble on my personal site listing a handful of ideas for iPhone apps.
The first was something I called “Supermarket Spotlight”, and it was described thus:
“Like Spotlight on your Mac, but for supermarkets in meatspace. You tell it that you’re in Tesco in Trowbridge, then start typing in the product you’re after. It tells you: ‘Aisle 12, section 2, top shelf, on the right if you’ve got your back to the cash tills.’ Either that, or it simply does the augmented reality thing and takes you there, beeping louder as you get closer, like a geiger counter.”
I never expected anyone to actually make it.

But blimey, someone has. And it’s Tesco, no less.
Their new app, Tesco Finder, does almost exactly the thing I described. It uses your phone’s location to determine where your nearest Tesco stores are, and gives you a list to choose from. Store specified, you just type a product name and off you go.

What’s funny is the App Store comments from Tesco staff, pointing out that this actually works better than the gadgets they’re given for using in-store.
Commenters also have plenty of good ideas for future extra features: prices would be good, and stock levels (you could find out there’s none of your favorite wine left before trekking across the store to fetch it), and this would be fun: upload a shopping list, and let the iPhone guide you round the whole store, satnav style, to get to all your stuff via the fastest and most efficient route.