Originally Posted by
corporate-wage-slave
The CBP interviews can be either landside, airside or downtown (New York and Washington). Generally they are indeed near the customs or baggage area, but when I had mine done in LAX it was landside. It's actually easier to get it down in Canada if you have the opportunity, they can't be done in Dublin or Shannon (and if Shannon is your main route then GE isn't worth having, though they do have the machines there).
I had my NEXUS interview in terminal E at YVR.