The Office returns April 10th with a new episode called "Dinner Party." The buzz during the strike was that this one was to be a classic.
It has been previously mentioned that 6 new episodes will be produced for the season and that mastermind Greg Daniels says he's "tempted to leap ahead to where we would have been." A Christmas script had been under production but will not be produced.
These are all things that were in the New York Times, which is a newspaper.
PS The first show to "return" will probably be Saturday Night Live on February 23 hosted by Tina Fey.