Yeah, the developmental snapshots for 1.8 have started. If you edit your profile in your launcher to "enable experimental development versions" and select 14w038b, then, when you generate new terrain, the new rock types (granite, diorite, and andesite) will naturally generate. They can also be crafted using quartz.
Keep in mind, they also changed the enchanting and villager trading systems.
So, it's not "officially" 1.8 ... but you can see a lot of what they are likely to include in the update.