I dont really know but chess.com scores the pieces as follows
Pawn-1 point
Knight-3 points
Bishop-3 points (but really its 3.25 as bishops are better in theory)
Rook- 5 points
Queen- 9 points (Rook+Bishop+1=Queen)
King-The King cannot be assigned a vaule but some say it approaches infinity.
Sorry, is there a FAQ page?