One of the most recent, and best bird books available is:
The Sibley Guide to Birds by David Allen Sibley, Alfred A. Knopf, New York, 2000.
Easier to carry around, and also good is:
A Field Guide to Western Birds by Roger Tory Peterson, Houghton Mifflin Company, New York, 1990.
A paperback full of advice on bird identification techniques is:
Sibley's Birding Basics by David Allen Sibley, Alfred A. Knopf, New York, 2002.