Letang finished off the first round of the shootout by putting a wrist shot just inside the right post. After Claude Giroux missed for the Flyers, Crosby clinched the win with a shot that rolled between the pads of Brian Boucher.
Crosby had a goal in regulation as well, giving him 22 for the season. Pittsburgh also defeated Philadelphia Tuesday and has beaten the Flyers four times in a row.
The win went to Marc-Andre Fleury, who made 31 saves.
Philadelphia's goals came from Jeff Carter and Giroux, but the Flyers lost for the eighth time in 10 games.
Pittsburgh is 5-0 in shootouts this season.