This morning I was syncing my iPhone and was prompted with a different kind of update message than what I've seen before. An update to the carrier settings for your iPhone is available. After digging around, I found that TUAW and AppleInsider had a bit more information.
AT&T is planing on rolling out a device that can help alleviate 3G dead zones in your home or workplace. MicroCell is a device that can provide a strong signal for up to 10 devices, and allow for up to 4 simultaneous voice or data connections via a connection to broadband Internet. No pricing information is available yet, and the AT&T MicroCell web page is still "under construction".