It won't be available en masse until the 17th of the month, but the gold build of iPhone OS 3.0 is now available to developers -- a promising sign that apps taking advantage of a wide variety of 3.0's new features (push notifications, in-app payments, and the like) will be available by the time it's released to the general public. We've been toying around with the latest cut here and have noticed a few small changes from beta 5; nothing groundbreaking, but notable nonetheless. Most importantly, iTunes is now offering movie, TV and music video downloads directly from the phone, which has caused the bottom navigation bar to be rearranged a bit. We also noticed that the App Stor
