Is it listed in the System Profiler?
Are you sure you have a compatible wi-fi installed? Take the cover off the back and make sure it is a Broadcom card as Intel cards won't work.
If it is a Broadcom card and you just need to install the kexts (OS X version of a driver), run NBI.
Running NBI immediately after you finish installing OS X and before it re-boots should be a part of any tutorial, but it wasn't part of the Gizmodo guide and has been reproduced on numerous other sites.
Mini 9 | OS X 10.6.7 | NBI 20100616212351| BIOS 05 | 32 GB Runcore | 2 GIGS RAM
10V | OS X 10.6.7 | NBI 20100616212351 |BIOS 06|160 GB|1 GIG RAM| 6 Cell Dell Battery
Functioning Hibernation
Back up Mini 9| OS X 10.6.7| NBI 20100616212351| BIOS 05 | 32 GB SuperTalent | 2 GIGS RAM