Teacher Resource Sites:
Principles and Methodology
Resources and Books on Methodology
Asher, James.  1977.  Learning Another Language Through Actions: The Complete Teacher's Guidebook.  Los Gatos, CA: Sly Oaks Productions.  See also http://www.tpr-world.com/.

Brown, H. Douglas.  1994.  Teaching by Principles: An Interactive Approach to Language Pedagogy.  Prentice Hall.

Finocchiaro, Mary & Brumfit, Christopher.  1983.  The Functional-Notional Approach: From Theory to Practice.  Oxford University Press.

Krashen, Stephen D., & Terrell, Tracy D.  1983.  The Natural Approach: Language Acquisition in the Classroom.  Pergamon Press.  See also Bilingual Education: Arguments For and (Bogus) Arguments Against , Theory of Second Language Acquisition, A Summary of Stephen Krashen's "Principles and Practice in Second Language Acquisition", Why Bilingual Education?.

Larsen-Freeman, Dianne.  1986.  Techniques and Principles in Language Teaching.  New York: Oxford University Press.

Nunan, David.  1991.  Language Teaching Methodology: A Textbook for Teachers.  Prentice Hall.  See also http://ec.hku.hk/dcnunan/ 

Prator, Clifford H. & Celce-Murcia, Marianne.  1979.  "An outline of language teaching approaches."  In Celce-Murcia, Marianne & McIntosh, Lois (Ed.), Teaching English as a Second or Foreign Language.  Newbury House.

Richards, Jack & Rodgers, Theodore.  1986.  Approaches and Methods in Language Teaching.  New York: Cambridge University Press.

Online Resources:
Second Language Teaching Methodologies - Eric Clearinghouse on Languages and Linguistics
Teaching Techniques - From www.eslabout.com
Whole Language, Whole Person - A Handbook of Language Teaching Methodology