They list replacement glass on the list at Silverstate Ford parts.

 

Ok, I can only speak for my 2010 4.6L F150 but the passenger side glass replacement is indeed a snap to replace! It took less than 2 minutes. The cracked one came off as previous posters said, with only a flat head screwdriver. The $20 replacement glass (comes with the plastic backing) simply snapped on. Piece of cake.