Iserson's Getting Into a Residency: A Guide for Medical Students by Kenneth V. Iserson (Galen Press)

The Ultimate Guide to Choosing a Medical Specialty by Brian Freeman (McGraw-Hill Medical)

How to Choose a Medical Specialty by Anita Taylor (W.B. Saunders)

Note that the Iserson text is available in the McGill library and the Career Planning Office. The others you would need to purchase.