...wicked
Yah but some people use them on every channel. 
 
I myself use it on my Master bus, it's part of my recipe for making stuff sound like it was made in a real studio :-)
 

But in a real studio would not every mic/line typically in go into the console?

LLyons
I mix into them, bottom of the stack.  I use the TOL switch.   I use them on instruments - sans VST drums.  The drums already seem to have been effected by a mix console.  I stay away from them on vocals. Depending on the mood of the song, I push them a little harder on driving stuff, and back the effect off on softer \ acoustic work.  I generally don't put them on a buss - usually if a track already has a console on it.  I seem to use them on every song...
 
Best Regards  

This.....but I use them on every track including vocals. I really like the overall effect that it has on the sum of the tracks.

The console emulations are very subtle to my ears. I use them more as a filter. The Quad Curve EQ has a Gloss switch and I use the console emu's as an anti-gloss switch. They are completely different than something like the Waves TG12345 or REDD.

bapu
But in a real studio would not every mic/line typically in go into the console?

+1 to Bapu's point.  Using it on ONLY the master buss won't give you the same result as a real world console.
This is from the Sonar documentation for the console emulators...
 
To get the full benefit of console emulation, you typically want to add the Console Emulator module to all audio tracks and buses across your project.
 
Keep in mind that the effect is accumulative, so the effect will become more noticeable as you add Console Emulator to multiple tracks.
 
The trick is to insert the Console Emulator module before you start mixing. All your mixing decisions will then be made based on having the Console Emulator module in the signal chain. When you are done mixing, you can globally enable/disable the Console Emulator module to A/B the results, and you will likely hear a noticeable difference.
 
You will typically want to insert the Console Emulator module as the first module.
 

I've been using the console emulators, placing them on each new track even before I start creating, turn TOL on and wind the drive up a bit.
 
I still can't hear what they do though...

If you want everything on the track to go through the CE, wouldn't it be in the last position in PC? That's my understanding.

I use them on almost all projects, add them once tracking and editing is done and before mixing really starts ... i have the feeling i need fewer changes to some tracks if NLS is in the chain ... I use it in (almost) all tracks @ end of chain (sometimes some instruments don't go well with it, so I might exclude a few tracks occasionally) and the bus plugin in the master bus (according to WAVES reocmmendations which do work best)
 
WAVES NLS is what I use mostly because it has got 32 different channels of 3 consoles ... the 3 consoles have different character so I select them based on the mood of the song ... but the 32 modelled channels are nice! it's not that I would claim to hear a difference between them, but since they are obviously slightly different, adding these different channels seems to get more separation and space between the individual tracks... totally voodoo black magic, but all explainable in an engineering manner :-)

michaelhanson
If you want everything on the track to go through the CE, wouldn't it be in the last position in PC? That's my understanding.

Hi Mike,
I believe that it comes FIRST in the chain so that all other modules in the chain will be equally "colored" by the emulator.  Check out the Sonar documentation for the console emulators

FFB, 
 
What is this engineering thing you speak of and where can I get some?

"You will typically want to insert the Console Emulator module as the first module, and make sure ProChannel has Post FX Bin disabled. However, you can also experiment with placing the Console Emulator module at the end and enable Post FX Bin, so all your effects and processed sound are affected."

Mojo,
Taken from your Console Emulator link above, in the 2nd sentence.  At the end, post FX bin.