The process to enable 3D is actually pretty straight forward.
As has been mentioned in the thread, the first process is to access the EZAdjust menu.
In order to do this, you'll either need the LG service remote or a universal remote capable of learning IR HEX. These include, but i'm sure not limited to, Logitech Harmony, Philips Pronto, One4All and RCA.
The IR codes are available herehttp://openlgtv.org.ru/wiki/index.ph..._menus_/_modes
You will also want to setup the InStart, InStop and perhaps PowerOnly codes.
Once this is programmed into your remote of choice, press the EZAdjust button.
You will be prompted for a service password which is 0413
You should then be presented with the EZAdjust Tool menu
Select Tool Option 5
Set 3d Display Type to 3D
Set 2D to 3D to On
Press Back on your remote and press EZAdjust button again, re-entering the password when prompted
Select Tool Option 6
Set 3D THX to 1
Press Back on your remote
At this point, you should be able to see the 3D Video menu under Setup/Picture menu and the 3D quick menu if using the Motion Remote. In my experience, this simply brightened the screen when enabled.
In order for the TV to correctly process 3D material, the InStop function had to be passed. This is bascially a factory reset, so be sure to make note of any settings as these will be lost.
Press the InStop command on your learning remote and enter the 0413 password.
This will reset the TV and power it off. Power it back on from the remote and 3D should now be enabled.
Lastly, in order for the TV to advise other devices of it's 3D capability, you will need to "download" the EDID data.
The service manual advises that all HDMI and RGB inputs need to be removed from the screen prior to doing this, so please remove all inputs from the screen.
Press the EZ Adjust button on your remote
Select EDID D/L menu. (US panels seem to have EDID AC3 and EDID PCM, you will need to select the audio method you're using)
Press the OK/Enter button and EDID download will begin
If Download is successful, OK is display, but If Download is
failure, NG is displayed. If Download is failure, Re-try download again.
I make no warranty against these instructions and following them is at your own risk.
I'd strongly recommend making a backup of your TV which can be done by entering the Installation Menu and going to TV Link Loader
Thanks for videkid for the Tool Option screenshots and to nony for all his great suggestions