My interview was this past Monday, and I am now a member of Global Entry (:
I had my interview at DFW International Airport in Dallas. I arrived first thing in the morning, located the office and signed in. There were already 8-12 people waiting for their appointments. After 15 minutes or so, a CBP officer called my name and led me to his cubicle.
We exchanged a few pleasantries, I gave him my conditional approval letter, my passport and my driver's license.
I also gave him my CHL (Concealed Handgun License) and informed him that I was unarmed (of course). In Texas, this is (usually) required when a CHL holder is showing identification to a police officer. Although it was probably not required for me to do this with the CBP officer, I wasn't 100% sure, and anyway I figured it couldn't hurt to show some proof that I'm "one of the good guys" (:
The officer asked me about my past and future travel plans ("Were your trips to the countries listed on your application for business or pleasure? Are you primarily going to use your Global Entry membership for business or pleasure?").
He then asked me a series of questions about whether I had ever been convicted of a crime, whether I had ever violated customs laws, etc. These were all the same questions as the ones on my application form, so I'm assuming that the point of this was to establish that I was who I said I was and/or to make sure I wasn't lying on my application form.
Then he registered my passport, took my photo and recorded my fingerprints (using a digital reader). He put a special sticker on the last page of my passport and gave me a few booklets with more information on the program and US customs laws.
I collected my documents, thanked the officer for his time and got on with my day.
The whole process took 30-45 minutes. I spent 10-15 minutes waiting for my turn, and then the interview lasted about 20 minutes.