Basically I followed these instructions.
1 - restore the install DVD to a USB stick
which you need to do because the USB is writeable and we need to modify some files on it
2 - Run NetBookBootMaker against the USB stick
BE VERY CAREFUL! Running on a real Mac against your HD will kill OSX!
Make sure you have 0.8.3RC4 since it fixes 10.6.2 to run on the Atom.
3 - Boot your Wind from the USB stick - press F11 on boot, or go into the BIOS and change the boot order.
4 - Install just like normal. Restart.
On the first run the trackpad didn't work properly - have a mouse ready
5 - Download the NetBookInstaller program and have ready to run, but don't run yet.
6 - Run the 10.6.2 combo updater. DO NOT RESTART!
7 - run the NetBookInstaller.
8 - Restart, and you should be running 10.6.2!
Stuff thats not working:
Ethernet update: install the network kexts from 10.5.x
Given that the only reason right now for doing this is to get find and sort by size back in the finder, I can't recommend it.
I'll keep looking for other methods.