Since we all will probably need to switch to the new nanoSIM included w/ the iPhone 5...I would really love to have an adapter ready to go to swap devices as I see fit...
I need an adapter the other way, to turn a micro into a nano. Yeah, I know it's impossible. Although two years ago I had to turn a mini into a micro, going from 3GS to 4, and the genius at Apple took a little device and made it so. I needed another one last year, same phones but different number, but the geniuses had no clue, and my DIY attempt did not work. I'm not going to try to cut down a micro to nano; I know it won't work, anyway.
Maybe next time they'll have a pico-SIM and I'll have to go through it again. Actually I hear that they might switch to an embedded SIM that can be reprogrammed by USB, which would be a relief.