Rules
High, Low, Jack, Game
The four words to remember when learning to play pitch are High, Low, Jack, and Game. These are the four points you'll be trying to score during each hand. High is the highest card played in the trump suit (don't worry -- I'll explain trump in just a bit). Low is the lowest card played in the trump suit. Jack, as its name implies, is the jack of the trump suit. The fourth point, Game, is the primary source of confusion for people learning to play Pitch. For now, just remember that in order to score the game point, you'll need to win tricks with lots of 10's and face cards (J, Q, K, A).
Trump
As you've probably already guessed, Pitch is a trump game like Euchre or Pinochle. Each hand, a trump suit will be chosen by one person. Then, for the duration of that hand, trump cards will beat any non-trump cards. This means that if Hearts is the chosen trump suit, cards in hearts will beat cards in any other suit. Unlike some other trump games, there is no concept of an off-Jack or any other non-trump card which beats a trump card.
Bidding
At the start of each hand, one round of bidding takes place. Bidding starts with the player to the left of the dealer and goes around the table once, ending with the dealer. During the bidding, each player is given the opportunity to make a "bid," indicating the number of points they think they can make if they were to choose the trump suit. The minimum number of points a player may bid is two, and the maximum is four (since there are only four possible points which can be scored -- High, Low, Jack, and Game). If a player does not wish to bid, he may "pass," and the bid moves on to the next person. If the bid goes around to the dealer and all of the other players have passed, the dealer must bid two points (this is called a "force bid"). Once any player makes a bid of two or greater, all ensuing players must either pass or over-bid the current bid. At the end of the bidding round, the player making the highest bid declares a trump suit by playing a card in the suit he chooses to be trump.
Playing
Since there are six cards dealt to each player, a hand of Pitch will contain six "tricks" or rounds. To begin each hand, the bidder must lead with a card in the suit he has chosen to be trump. Play then moves clock-wise around the table one time during each trick. Players must follow suit during every trick, with the notable exception that trump may be played at any time. If a player does not have a card matching the lead suit, he may throw any card in his hand. At the end of each trick, the player of the highest valued card takes the trick and places it face-down in front of him. This player must then lead the first card of the next trick.
Scoring
As stated earlier, a total of four points may be scored during each hand. The objective of the bidder is to score at least the number of points which he bid. If the bidder does this, he "makes" his bid and is credited the number of points he scored. If the bidder fails to make his bid, he is penalized the number of points he bid. Non-bidding players are credited with any points they make. Since the score is kept from 11 down to zero, a player who makes three points will have three points deducted from his score. Likewise, a player who bids three and makes fewer than three points will have three points added to his score. When any player reaches a score of zero or less, they have won the game. If two players reach zero during one hand, and one of the players was the bidder, the bidder wins the game.