I initially had a phone interview with the person under whom I will be working, if employed. It was very general, about my resume and work experiences and what kind of skills I have, willing to relocate etc etc.
Then I was contacted again after a few weeks and was asked if I will be interested to fly to Houston for an interview. I said ok and scheduled a date. The interview was scheduled for the complete day, from morning 8 to evening 4. I was greeted by the same person, whom I will be working and then he took me to his office and asked me if I would like to have something to eat/drink. Very friendly conversation, I did not feel like it was an interview. then he started to talk about the work he and his department is into, and he showed me some of the tools they work and what kind of work I will be doing if hired. Then I was introduced to one of his group member and he explained in detail about the work he is doing and the scope of work for me. then we had a plant tour and met a few people. then I met a manger from other department who interview me for about 30-40 mins. he asked simple question, about my work/experiences and asked me a few situational questions like what will you do if some kind of problem arises, how did you handled a tough situation/challenge at work etc those kind of question and I was sent back to the 1st person again. Then we headed out for lunch with one of his group member for about 40 mins. then we talked for some more time about Houston, development in houston, how companies sustained in Houston during the tough economic times etc and then went for a walk within the company to meet few more people from various department. Everyone was very friendly, it was all casual talk, what did I study, where did I graduate from etc.
The main purpose of the interview is to make ourself comfortable with the environment and people of their company. Atleast that's what I felt and feel.
So guys be yourself, positive and confident. If you are easy going then its good.