This weekend begins the intensive work on the Sandy-ravaged tunnel on the R and (late night) N line connecting Court Street station to Whitehall Street in lower Manhattan, scheduled to last until October of 2014. On weekends (presumably this means from 11:30 p.m. Friday and 5:00 a.m. Monday) and late at night (again presumably 11:30 to 5:00) Monday to Friday, the trains will run in both directions on the Q line over the Manhattan Bridge between DeKalb Avenue in Brooklyn and Canal Street in Manhattan. On weekdays (presumably from 5:00 a.m. to 11:30 p.m.) R trains will run between Court Street and 95th Street in Bay Ridge in both directions. They will also run between Whitehall Street in Manhattan and all points north in Manhattan and Queens.
There are no other planned diversions or cancellations directly affecting service at any local stations this coming weekend or the following week. For planned service changes, including skipped stations, that may affect your travel plans on other parts of the system, please consult MTA Info or The Weekender.
Source: Brooklyn Heights Blog