Very good and simple tutorials from Jose Luis Diaz for dialogue editing. I recommend also the book "Dialogue Editing for Motion Pictures: A Guide to the Invisible Art" from John Purcell (2nd edition).
Dialogue Editing 1: Organization http://www.youtube.com/watch?v=zDwQCO7v1ME
Dialogue Editing 2: Basic Transitions http://youtu.be/9MqSD7E5K7M
Dialogue Editing 3: Using Reverse Room Tone http://youtu.be/Jrfb6MGJHpc
Dialogue Editing 4: Aligning Shots http://youtu.be/RKwf5UWKh2c
Dialogue Editing 5: The Telephone Split http://youtu.be/SqHKaPo2tY8