I'm using Mac OS X 10.4.11. But I know that the guide works, because when I'm in chooser without doing the steps, nothing is there, following the steps then makes my PowerBook G3 show up. (The guide mentions that AppleTalk won't work in Mac OS X while this configuration is running.)
The guide itself says "Appletalk for SheepShaver/Basilisk in Leopard or Snow Leopard (32-bit)." So I assume it works with Snow Leopard.