The internship was listed on the Red Cross website; an email/call to the HR manager and I had a date for an interview. I interviewed with the HR manager, who basically just asked why I was interested in the position and told me about the organization and some specific things that were going on at the time. I also talked to the finance director (who I wound up working for). It was pretty simple, she just asked about some things on my resume and said a little about what the job would entail.
Granted, this was for an unpaid internship, so YMMV.