Patter Manual
Robert Cole & Peter Phillips. Bought it, never used it!
One guy I know had the exercises on tape - my problem was that I no longer had a tape in the car. Great idea though.
My problem with spins was getting the patter to match the actions! What fun!
As others have said, practice wherever you can - out loud. Move your hands and feet at the same time as if you were touching the controls.
Also, remember to personalise your patter - You will retard the trottle. Then you hold the attitude..... When you move the control column.