Although you may not always have the luxury of starting your training several months before teachers begin teaching in a computer classroom, start as early as you possibly can. If you have enough advance time to have them visit classes taught in the computer classroom, new teachers can observe a variety of teaching and classroom management techniques. If you have only two weeks to complete training, have your first training session two weeks before classes begin. Teachers may not be able to observe in a current class, but they will then have time to view videotapes of successful classes in a computer classroom, as well as adequate time to learn the hardware and software they'll teach with.
Even if you have only two days, take as much of the time as you can for modeling of effective computer-classroom teaching techniques and hands-on work in the computer classroom.