The Professorette has three pieces of advice for the academic suddenly deprived of the services of his or her dominant upper extremity:
1. This sling. In tasteful yet comfortable black spandex.
2. One can write on the board with one's non-dominant hand. Go slowly and carefully. Switching from a blackboard to a whiteboard (or vice versa?) might be helpful.
3. In OS X: sticky keys mode.