G'day all,
 
Apologies for asking such a noobie question, but can anyone out there with a N/A AW11 show me where the Idle-Up mechanism is located? Under there, everything looks like the bit in the manual and I can't find the damn thing (I bet I'm looking right at it)! ;)

Are you referring to the vacuum idle-up or the wax type idle control / cold start system?  I believe they are both part of the throttle body, however I couldn't tell you which one of the few vacuum hoses on the TB is the idle-up for alternator load.
 
Some more info with pictures from goolge...
http://www.locostbuilders.co.uk/viewthread.php?tid=80900
 

Hmm, not sure what the 'wax type' idle control means, the manual by Toyota actually refers to it as the idle-up system, which is a compensatory mechanism for when you enable the aircon. When I turn on the a/c at low idle speeds, the compensatory system isn't working and the idle drops to very low and the system cuts of the a/c to keep the engine from stalling. So I'm not chasing a controller for fast idling and cold starts, but the compensatory mechanism for when the a/c grabs revs

Sounds like you need to troubleshoot the vacuum lines around the throttle body then, and tracing one back to the idle-up valve.  Hopefully someone who knows what they are talking about (namely not myself) can offer more detailed assistance.
 
From the link I posted above ...

... you should have one of the vacuum tubes connected to an idle up valve. This works with a signal from the ecu basically opening a valve so that the vacuum tube is open to atmosphere, thereby increasing the idle speed. This is used when you are chewing a lot of amps from the battery with lights, heaters and fans. It idles up to let the alternator provide enough charge.

anarchisttomato the a\c idle up is not apart of the trottle body. on the passenger side of the engine bay there is a large VSV  type valve, it bolts to the side of the strut tower and sits above some large white (main power) connectors. You can see it by following a couple of large vacumn lines going from it to the main rubber intake hose before the throttle body (1 hose goes to the intake hose, one goes to the back of the throttle body below the TPS)

I am assuming this is a 4AGE, not GZE

if your only having idle up issues which your a/c on then likely this unit is faulty, check it as per the manual.

you can see it in this old pic I found. on the side of the strut tower between the fuse box and strut tower. Never mind that this is a GZE, its actually a 4AGE with a supercharger. Long story.