The are three basic ways to set up a co-taught lesson, but anyone who's ever done collaborative teaching knows that there's a lot more that goes into a successful partnership than the structure of a lesson. It's based more on the level of trust, understanding, and mutual respect within the team.
Having team-taught for six years with twenty-five different teachers, playing the roles of push-in support, co-teacher, and classroom teacher in various partnerships, I've seen the truly wonderful aspects of co-teaching, as well as been frustrated to the point of tears. I developed these questions after four years of experience with this model to strengthen my own partnerships. By starting with this discussion at the beginning of the teaching-relationship, you can build this relationship while strengthening the instruction of your students, rather than taking away from it.