NOTE: This is for the North American version of Phantom Hourglass.
Phantom Hourglass is the first Zelda game to include online, multiplayer, play. Overall, it is a great addition. Basically, how it works is that there are three rounds, each a 120 seconds long. Each round consists of two parts, one part where you are Link, and the person you are playing is the Phantoms. In the second part, you trade positions, and you become the three Phantoms and the opponent takes over as Link.
To start online play, you must first have wireless WI-FI internet. To reach the online play screen, you must open your file, from the file select screen, and hit the start button. Choose the battle option, and it takes you to the online play main screen; choose the Nintendo WFC option, and use it to connect to your wireless internet network.
You then must choose who you want to battle. You may battle a friend, however, this option requires you to have their friend code. But no fear, if you don't have friends, you can choose to battle either a rival, which is someone that has around the same stats that you have, in either North America or worldwide, or a random person with random stats, in either N.A. or worldwide.
The system automatically searches for other online players and hooks you up with an opponent. One of the two is randomly chosen to be player one, and that player gets to choose the stage style and gets to go first. There are eight stage styles to choose from, ranging from very small to very large stages. There is also a randomizer option that chooses a stage for you.
When the game begins, the object of player one (Link) is to run around and collect Force Jems, all while avoiding the deadly Phantoms (player two). Once player one gets a Force Jem, they must carry it over their head back to their color-coded base. When player one succesfully drops the Force Jem in his/her base, his/her points go up. Larger Force Jems equal larger point amounts, however, larger Force Jems also weigh more, and slow Link down.
However, if you get hit by a Phantom, you switch sides with your opponent. You then get to control the Phantoms, and your goal is to track down Link and attack him. The bottom screen, the touch screen, then becomes a map, where you can use the stylus to draw lines that your three Phantoms will follow. The Phantoms will automatically attack Link when they see him, however, they do not move as fast as Link, so there is a chance he will get away, but one hit will do him in. The object of your turn is to keep Link from getting Force Jems into his base and scoring points.
The game also contains a few extras. One of which are power-ups. There are various types of power-ups. Power-ups are color-coded, which means that player one can only pick up red power-ups, and player two can only pick up blue power-ups. Power-ups range from everything from increased speed to extra strength for Link, and upgraded attack to subtraction of time for the Phantoms. It is possible to destroy the other player's power-ups too, by running over them.
Overall, the online play is an AMAZING addition to the Zelda series. The controls are very natural feeling, and the game itself is a lot of fun, which is what matters the most. It is a great plus being able to challenge anyone, and not having to enter friend codes just to battle someone. It pretty much guarentees you that you will always have a person to play with, no matter what the time of day. The only thing I do feel that the online play is missing is team play. I think it would be a great upgrade if Nintendo had included an option to play the game on teams with either random people or friends. Who knows, maybe it will be in the next game.
In conclusion, it is great fun, and a smart move by Nintendo.