Either Kathy Smith Kickboxing, Powerstrike Millenium 3, or the instructional tape (but not workout) from Katalin Zamir (what's her system called). The last one is an excellent, 1-hour-long tutorial on form, and the others have good form pointers.
IMO, none of Cathe's kickboxing workouts are appropriate for beginners, as they presume a certain level of skill for safety.