I’ve used this Photoshop tutorial once already, with fantastic results. I recommend you Right+Click on the video and Download it to make it easier to follow along.
Some great video of the current construction progress at the Apple Campus 2 site. Apple certainly isn’t wasting any time here. The size of this thing is just amazing. The “raised” circular area will be the courtyard in the middle of the building and will actually be the ground level. The area around it will eventually be sub-ground level floors and parking.