Manning completed 12 of 18 passes for 163 yards. Amani Toomer caught four of them for 80 yards and the two touchdowns.
Jacobs finished with 54 yards on 14 carries for the Giants, who reached the NFC title game for the first time since 2001. New York will play at Green Bay next Sunday, with the winner moving on to Super Bowl XLII.
Romo threw for 201 yards, one score and one interception on 18-of-36 passing for the Cowboys (13-4), who have not won a postseason game since 1996.
Marion Barber had 129 yards and one touchdown in defeat.