Hi, I'm getting a similar issue. I've installed from 10.6.3 retail disc image and upgraded to 10.6.7 using the following steps:
Install 10.6.3, wireless works fine
Download netbookinstaller 0.8.4 RC1
Run netbookinstaller 0.8.4 RC1
Download and run Combo Updated 10.6 -> 10.6.7
Before reboot, run netbookinstaller 0.8.4 RC1 again
Wireless does not connect - Airport shows up as 'off', won't toggle back on
Run netbookinstaller 0.8.4 RC1 again
Wireless still not working
---------- Post added at 11:54 PM ---------- Previous post was at 11:19 PM ----------
Okay, I seem to have fixed this. I was trying to use NBI 0.8.1 RC1 because obviously without wireless I couldn't use any other version.
So, I went on my PC and I downloaded the version of NBI ***351, used TransMac to copy the app over to a HFS+ formatted USB drive and copied it onto the 10v. Installed with default settings, rebooted and voilą the wireless is working again!