Its showing up for me now too. So is there any way for me to get all my old photos (in iPhoto/Aperture) into the iCloud photo library yet, or do I need to wait for next year when 'Photos' for Yosemite is released. Turning on iCloud photo drive has removed all my synced photos from my iPhone. So I may turn it off until the new program is released if this is the case.
Thanks for clarifying this. I've switched it back off. Until I can get all my photos from iPhoto into I can't see the benefit to using it yet. Looks like I was a bit early in upgrading my iCloud storage to 200GB!You can only enable it on iPhones, iPads & iPods for desktops you have to wait till they release the photo app.