Squire's Fundamentals of Radiology (most recently by R.A. Novelline) is recommended; a broad, not overly in-depth overview of lots of stuff in radiology. (With some attention to common stuff so you can follow along with CXR, chest/abd CT, etc.)
Felson's Principles of Chest Roentgenology: A Programmed Text, (by L. Goodman) is a nice, Dubin-like introduction to reading CXRs. Also quite good.
If you wanted to get more in-depth, ask residents on your rotation.
Good luck.