Most web based training interfaces allow you to move and copy workouts by simply dragging to new date or dragging and holding CNTRL to copy to new date.
Sometimes I just can't run on the prescribed day (either other commitments or injury) and it is tedious having to either edit custom workout date manually and for training plan workouts they cannot be edited, copied or moved at all within the Connect interface.
Polar and Magellan interfaces both allow drag functionality.
