A Common European Framework of Reference for Languages: Learning, Teaching, Assessment
The full text of the CEF can be downloaded from http://www.culture2.coe.int/portfolio/documents_intro/common_framework.html and this site also gives details of how a hard copy may be purchased.

Brown, G and Yule, G (1983) Teaching the Spoken Language, Cambridge University Press, Cambridge
The subtitle of this is 'An approach based upon the analysis of conversational English', but it contains many useful transferable ideas.

Bygate, M (1987) Speaking, Oxford University Press, Oxford
Again, for EFL teachers, but it is very detailed.

Nunan, D and Lamb, C (1996) The Self-Directed Teacher, Cambridge University Press, Cambridge
The reader is directed principally to the chapter on classroom talk (pp 60-103), which is primarily about teacher talk.

Underhill, N (1987) Testing Spoken Language: A handbook of oral testing techniques, Cambridge University Press, Cambridge
A comprehensive review of techniques required to design, implement, mark and evaluate oral assessment tools.

Ur, P (1981) Discussions That Work, Cambridge University Press, Cambridge
EFL, but contains lots of practical examples, for use with different levels.

Ur, P (1991) A Course in Language Teaching, Cambridge University Press Cambridge
Whereas the previous text focuses on speaking skills, this is more comprehensive, but the chapters on speaking, assessment and pronunciation contain updates and new ideas.