you can find a good example of what to expect at www.oneaddplace.com. Several of the questionnaires are nearly identical to the actual questions you'll be asked.
They will ask questions as much to rule OUT other problems as to rule IN ADHD. Every person is different so you can't expect to be identical to others. Spend a few days here and you can see that.
I had to answer a questionaire that seemed 7,432 pages long. I think it was really only about 5 pages tho. After the initial visit, it was a piece of pie.well for me it was just chatting with the psychiatrist. he asked a whole load of questions - which i answered and he said yup, you are an ADDer. then talked about ritalin, the effects, and wrote a prescription and told me to come back in a week after i had tried the rit. eh, voila. simple like that.