Scrivener for Windows is due for release on 7 November. See the blog post here. Note you can get an effective 20% discount on a pre order if you order now and use the “NANOWRIMO” coupon code. You get your serial number ready for when 1.0 is released.
At UK pricing, my copy cost c. £22.87, which is an absolute bargain, and still would be without any discounts.
Update: Actually was released in November, not December as originally stated. Now up to version 1.0.3, so the guys are actively developing the software and sorting out bugs. Good work.