Check out this informative page with pictures about former creeks in the Mission on Burrito Justice. It has maps dating back to 1859 and is followed by a great discussion by some pretty smart people. Click on the title or HERE!
The SFPUC and nifty engineers at the Dept. of Public Works also worked with the Oakland Museum of California to develop a cool map for download that highlights all the old San Francisco creeks and watersheds! It is called the Creek and Watershed Map of San Francisco.