The queen combines the powers of both the rook and the bishop. As such, it can move horizontally, vertically, or on the diagonal. In a sense, it's like the king in that it can move in any direction. Unlike the king, however, it can move far in one direction so long as there are no pieces in its path.
In the diagram, the queen can move to any of the squares marked with an "X" Like the rook and the bishop, the queen captures as it moves. In this position, the queen can capture the enemy rook, knight, or bishop, but it may not jump over any of the pieces on the board.
The diagram shows clearly how powerful the queen is. Use it carefully. As you will learn, it is very risky to bring the queen out early because, if you lose your queen, you are likely to lose the game!