The store's design was approved back in 2011 by Steve Jobs and construction starts every morning (even on Sundays) at 7am. The location is expected to encompass 12,000 square feet, and while it was supposed to open last November, the glass design is supposedly slowing things up. The plans for the store are supposed to include a "visually floating roof" and a large stone wall separates the front of the store from the back.
Pictures of the site really don't give away too much because of the fencing around the location, but the sheer size of the place can be seen from the photos. This store alone will probably raise Windex sales in the area by 50%.
Construction of Palo Alto Apple Store
source: Flickr via TechCrunch