[UPDATE BELOW] The local chapter of the union that represents nearly 3,000 of the NBC's producers, writers and technicians is threatening to walk out during the network's "Christmas in Rockefeller Center" special tonight—potentially denying millions of viewers the pleasure of seeing a light switch get flicked. The show is supposed to be broadcast tonight starting at 8 p.m., hosted by Jane Krakowski (30 Rock) and Zachary Levi (Chuck). Musical guests include Aretha Franklin, Rod Stewart, Rob Thomas, Alicia Keys, Jo Dee Messina, Barry Manilow, Shakira, The Muppets, and The Roots.

Con Ed and the union representing 9,000 members agreed to extend their contract negotiations for another three days, after Governor David Paterson 

