Some books recommended to me by residents:
1) Baby Miller (some programs supply it, most have you read it in first few weeks/months)
2) Lange: Clinical Anesthesiology (a little longer but an easier read than baby miller)
3) Faust: Anesthesiology Review
4) Anesthesia and Coexisting Disease
5) Pretest Nurse Anesthesia (good practice questions)
6) Anesthesiologist's Manual of Surgical Procedures (haven't used this one personally, some love it.... others tell me it is a little dated)