3G MicroCell site is now up and running where you can enjoy some video overviews and get a good gander at what the finished product looks like (it's way better than the version briefly shown a few months back, if you ask us). Availability of an unlimited calling add-on is confirmed here, and any calls that originate on the MicroCell before being handed off to AT&T's old-school towers will be kept completely out of your minute bucket as long as you sign up for the unlimited package. Also notable is that the carrier officially recommends placing the box near a window so that its GPS receiver can get reception -- like its cousins on Sprint and Verizon, the MicroCell includes GPS so that it can't be used out of the country. So far we're not able to find a ZIP code that works with the availability checker (including the rumored limited release markets mentioned last week), so if you get through, give us a shout.
Update: ZIP code 28201 works, though it doesn't let you see plans or buy online -- it just hooks you up with the addresses and phone numbers of nearby stores. There'll be a few calls being made in the morning, eh? Thanks, ryan0816!