I applied online. The process took 1 day. I interviewed at IBM (Herndon, VA) in Dec 2015
Interview
There were three interviews. Two behavioral interviewers, and one case interview. The three interviews were thirty minutes each. All of the interviews were just myself and another interviewer, and all of them were with a different person each time.
If you are worried about the case study, it isn't hard. My case study was easily solved using basic math and simple logic. Was also asked to provide my recommendations, which in my opinion was quite easy to do.
The entire interview day was well organized. Everyone was very friendly. They had employees assigned as "greeters" to help calm interviewees nerves, and guide them to their interview location within the office.
I applied through university. The process took 3 weeks. I interviewed at IBM (Chicago, IL) in Oct 2013
Interview
I submitted a resume through university recruiting then received an invitation to interview. There was one day of 3 interview - 2 behavioral and 1 case - and I then received a call about 2-3 weeks later with an offer.