Summer of 2010 will come to an end on Wednesday, September 22nd, and Fall will begin. The autumnal equinox marks the beginning of Fall, which will occur at 10:09 pm CDT. On the equinox, the sun rises directly in the east and sets directly in the west. On the autumnal and vernal equinoxes, one can find the exact cardinal directions of east and west by using the sun.
The image below indicates the illumination of the Earth by the sun on the day of an equinox (image from Wikipedia).