I got a few of mine as early as two days after I submitted my completed application (mid October) and the rest sort of trickled in over the next 2 months. I think I've pretty much heard from most programs one way or another. It's actually funny that I got rejected from a few small name programs while I was granted interviews by the bigger name ones. I only applied to the SE, South, and Southwest though (one or two in Midwest too), so for the areas that I chose I was happy with the interviews I got overall.
University of New Mexico
University of Arizona
University of Miami
University of South Florida
University of Oklahoma Health Sciences Center
Baylor College of Medicine
University of Mississippi
Lousiana State University Health Sciences Center
University of Texas Health Science Center at San Antonio
University of Cincinnati
I got a total of 13 interviews out of 24 programs, so it wasn't too bad. I felt that these 10 were the ones that best fit what I was looking for and were the easiest to schedule. I really wanted to go to Lexington, KY for their interview, but none of the dates worked out, so they were the only real program I had to reject but didn't want to.
Good luck on the rest of your interviews everyone! I hope to see you on the interview trail (I've made friends and exchanged numbers/e-mails with other applicants from almost every interview so far. Residents/faculty/applicants have told me that I'm one of the friendliest applicants with a great sense of humor they have ever had an interaction with, so that's always good to hear).
