Alright, well played, AT&T: you've sort of managed to undo Apple's unfortunate move of eschewing nearly two decades' worth of deeply-entrenched SIM card standards in favor of a new one that literally nobody in the consumer cellphone world is using -- and for that, we thank you. We're being told that these new SIMs are now being sold in AT&T stores for $15 and will work both with the iPad 3G and... well, literally every other GSM device you've ever owned, thanks to a couple of well-placed perforations that can turn the standard SIM into a micro SIM. This is presumably a preemptive strike to support the next-gen iPhone, too, but otherwise, you can go ahead and use the big card without busting out the little one. Trust us.
Update: Our tipster wrote back in to say that they're actually not being sold in stores yet, so if you've formed a line outside your local brick-and-mortar, go ahead and turn in for the evening. Sorry, folks!