We're a small non-profit called GNU/Linux Matters and we maintain a website called GetGNULinux.org. It's an introduction to Linux for everyday Windows users, translated in four languages.
I've seen a demo of Wubi by René Dittmann at Ubucon and I was very, very impressed.
Since our target audience is exactly the kind of people that would want to use Wubi, we are thinking of recommending it on our pages.
We "need" two important things before we can safely send many newcomers to wubi, and this is
1. Ubuntu 7.10
but as I can see, you're working hard on this it seems
2. A little more security warning
Specifically (correct me if I'm wrong), there is nowhere written that it's recommended to de-fragment the hard drive before installing. Also, Wubi mounts NTFS partitions on the Ubuntu desktop by default with write enabled; this is rather scary...
So the goal of this email is simply to give a little encouragement (and kindly ask for a little more security precautions). We'll be really happy to promote this great way of installing Ubuntu.