using your iphone as a plane boarding pass

A while ago I read this post (linked from here) which tells about how Gerald Buckley had successfully used his iphone to display his boarding pass and get the barcode scanned at the boarding desk.

Well, I just tried that this morning, and... it worked, much to the amazement of the guy at the desk. Reading the comments on both posts, it seems there's nothing new to it though, people have been doing this for ages, even on other devices.