Initial phone screening with HR rep within a few days of submitting application online. Asked about some of my experience based on my resume, what I knew about the company, etc. Scheduled an in-person interview at the New York office two days later. I completed a written form that asked me to describe my most rewarding work experience. It also included some extremely basic math (percentage) problems--don't worry at all about them. Then I interviewed with the HR rep, then with the manager of the negotiator team. All were very nice, straightforward, up front about work expectations, salary, and the company. Definitely an inviting atmosphere, kind of casual, laid-back company culture.
They offered me the role a day or so after interviewing; I turned it down mainly because it wasn't worth the commute into the city, and it's not exactly what I want to be doing with my degree. Otherwise, it seems like a good position. Base salary is a little low at $30,000, but they said it's normal for you to make $50-60,000 with commission as long as you're doing the job right.
Note: Even though it's largely commission based, it's not a sales position--the negotiator deals with the creditors, like credit card companies, and settles the clients' debt that way.