Northwoods used to have a very good recruiter. She's since left the company. However, I applied online and I was called within about a half hour. It was even more surprising since I applied at around 7:30 at night. She scheduled me for a phone call to cover basic technical experience. That went quite well, and after that I was scheduled for an in-office interview. That interview was mostly a technical interview, where they checked to see if I could speak about what was on my resume in a vaguely intelligent manner. It also had some general social elements to see if I was going to fit into their culture.
After that, they scheduled me for a second interview and a technical interview. Despite being told at the first interview that I should dress casually for the future interviews, I arrived at the second one in a suit and tie. I had just come from a funeral, and so they understood, but one piece of advice would be that if you're interviewing at Northwoods, go ahead and get there in a polo shirt or sweater, but don't bother with a tie (or even collar necessarily). Jeans are more than OK.
My second interview went pretty well. There were some social elements and some more general skills background. After the interview, they walked me out, and I had to ask about the technical interview. It turns out that the product officer who manages the developers wasn't in that day because he was moving, so they didn't have it. I skipped it entirely. I know that usually they do a paired programming session now if they're serious about hiring you.
Finally, they had me go to a dinnerview. That's an informal process where they take you out to eat, talk to you, and generally figure out if you're going to fit the culture of the company. It is possible that you wouldn't get hired after the dinnerview, but if you're there, then they're pretty serious about you, and you can relax and try to be yourself. It's probably better for you and Northwoods if you do, since you'll know better whether or not you'll fit in there.
Overall, the interview process isn't too hard, but it is very long. Sometimes they can speed it up if they really want to hire you or if you're from out of town, but that's rare. It took me 3 weeks. I wasn't in a hurry, but I think that's not too far outside of their norm.