Yes - ask them what format the interviews take. I would always be happy to explain that we follow a screening, followed by a 'cultural fit' followed by a skills/competances/presentation format over the three stages. This should allow you to prepare adequately, bearing in mind that you can never anticipate every question, and you still need to have what the company is looking for, no matter how well you prepare. It's surprising that some (inc Big4) companies invite you in for one type of process, then conduct another - only for both sides to be disappointed by the outcome. A decent compnay will have an open, and consequently effective process - have you had a look at the McKinsey, BCG etc websites for case studies etc?