The Learning Traveler, Vol. 3: Teaching Abroad. 4th ed., New York: Institute of International Education, 1984-1988. 
Perkins LB2283 .T42
This work contains a description of employment opportunities abroad on every educational level, both teaching and administrative, full- and part-time. Part 2 is a list of 200 study abroad programs for teachers and administrators. The information is arranged by country.

The ISS Directory of International Schools.  Princeton: International Schools Services, 2000/2001.  
Perkins Ref  L900 .I83
According to the preface, the intention of the ISS Directory is "to provide clear & easy access to some basic information about American-style primary and secondary schools throughout the world." Although this source is not intended to help find teaching jobs abroad, its currency will supplement the slightly dated information in Schools Abroad of Interest to Americans.

Schools Abroad of Interest to Americans.  Boston: Porter Sargent Publishers, Inc., 2000-2001. 
Perkins Reference: L900. S33 
Quoting from the preface, "the book's primary purpose is to objectively describe some 975 elementary and secondary schools in 132 countries of interest to young Americans and others seeking pre-college programs of study abroad." Although not a guide to finding teaching jobs abroad, this directory might prove helpful to individuals seeking such work.