Some great blog posts about anesthesiology.
A teriffic, free, and well-written introduction to anesthesiology: Understanding Anesthesia by Karen Raymer
Free, well-produced textbook from U. Toronto: Anesthesia Clerkship Manual
Interactive and well-produced learning modules on the basics of anesthesia: Royal College of Anaesthetists Guide for Novice Trainees.
Jeff Steiner's free book on obtaining a residency position: Getting Into Anesthesiology