Online lessons in ScienceMOO - a Collaborative Virtual Learning Environment  (These lessons involve both sychronous and asychronous activities)
3)  Online interviews with Master Teachers in ScienceMOO - http://sciencemoo.org

Student instructions - http://home.adelphi.edu/~murfinb/classes/sec-sci-content/interviews/student-interview-instructions.html
Instructions for Teachers - http://home.adelphi.edu/~murfinb/classes/sec-sci-content/interviews/teacher-interview-instructions.html
Sample online interview  with master science teacher