In the month of September, 2011, Mercury goes retrograde from the 3rd to the 18th. During these days it is best advised to stay put without any major works. Because all your efforts might end in vain. Instead focus on undone works and the like.
The days marked in green are the pre-retrograde periods when the Mercury slows down.The yellow-colored days are the period after the retro-grade when you can go about with your normal day-to day activities without much effort.