Google's "Googles" in the iPhone app seems to be the best software implementation I've seen so far. It's still pretty clunky and relies on a network connection to display the resultant material, which makes it only as effective as the cell-phone coverage in that area.

I think the thing that I don't like most about it is the one-way "black box" ness of the experience -- there's no way to know what you'll get out of it. I scanned one in a food magazine and got a bunch of mp3s that I couldn't download on my phone. HEY GREAT.

It will be supplanted by the much more useful Near Field Communications chip.

It's worth considering how web programmers are going to get paid for HTML5 webapps in a better fashion than the 'honor system tip jar' method in place today. Right now iPhone app devs can monetize their work, right now. That part of the puzzle, getting paid for HTML5 work, that needs to happen sooner rather than later.