The celebrations have started in Europe and Oceania, anyway! Players in these regions have started to receive their Onyxian Whelps in the mail, along with a letter welcoming them to a new year in Azeroth and a feat of strength upon logging in. This probably means that those of us in the United States (and Canada and whatever other magical lands are in the region) will be getting ours tomorrow. Considering Pilgrim's Bounty also starts tomorrow, it's kind of exciting! It really is a holiday in Azeroth.
The screenshot above comes from Enduser of Ghostlands EU. Since most of us here at WoW.com are US players, we're in dire need of screenshots! If you have any, please send them our way along with your character name (if you want credit for it) so we can add them to a gallery!