There is a book called the flying instructor patter manual, by Cole(i think) which might help, from what I remember the patter was in a 'military format'.
On the other hand you could write down the important key points and write your own script. Then keep practising it, when you have a spare moment, or while you are driving your car.
I'm suprised no one has never produced a instructors patter casette or CD, ideal for use in your car.