The bishop chess piece is an important piece but often times their power is not revealed until the end of the game. You get two of them at the beginning but don't waste them.
The bishop is limited to diagonally movement in any direction for as many free spaces as it wishes. However, since this chess piece can only move diagonally it limits the total number of spaces it can access on the board to 32 on a traditional board. This also limits the piece to either the white or black squares depending on the side.
Depending on where the bishop is located on the board it's movement is limited anywhere from 0-7 spaces assuming that the board is empty. If the piece is in the middle of the board, for example, it can only move up to 3 spaces in 3 of it's 4 potential directions. On the other hand, if it's in the corner then it can only move up to 7 spaces and only in one direction.
For these reasons, the bishop may be considered less powerful then the rook which can access all 64 spaces and is only limited to 14 spaces at any one time assuming no other pieces are in it's way.
The bishop is commonly found in many end game scenarios. This may be because the bishop is many times most powerful after other pieces have been removed from the board. After a board is empty it gives the bishop the freedom to move for long distances.
Chess pieces can come in many styles so the bishop will look different from set to set. Staunton style is the one most people are probably familiar with since this is the tournament standard.