Scrivener has a deal for NaNo, but they don't offer a Windows version. For those of us who use Windows, we're SOL.
Well...not really. 
If you want something similar for Windows, try WriteWayPro. You can download the demo and try it out for thirty days. I've heard good things about it from a lot of writers, including Larissa Ione. Also, it was created by Lara Adrian's hubby, so it's much more writer-friendly than many other programs out there. WriteWayPro is also on Twitter, and I found them (him?) to be very responsive.
There's also a special coupon code valid until November 30, 2009: $20 off the WriteWayPro download version. Just type NANO-PRO20 when you check out.
Disclaimer: I'm not in any way, shape or form related to or employed by WriteWayPro. I haven't received any monetary compensation for this post. I have, however, downloaded WriteWayPro, and am currently drafting my novel with it.
