The iPad 3Gs are not in stores til this evening
, but those who pre-ordered and had them shipped are already receiving the devices. Mine arrived an hour ago or so, and I've been playing around with it a bit since then.
Obviously it's pretty much identical to the iPad WiFi, with a few marked difference both in software and hardware.
The top has a black plastic area instead of metal to allow for better 3G reception. It wraps around from the back of the iPad 3G to flush with the bezel on the front - so you've got both a bit of black in the silver frame of your iPad, and the black