From wikiHow.com. Damn hilarious article. And it's supposed to be a SERIOUS website.

HOW TO DIVE IN SOCCER

Diving, officially known as simulation, is the act of faking a foul or injury in soccer. Its supporters call it strategy, its detractors call it cheap (and the players that practice it worse), but a soccer player is well served in knowing how to draw the referee's ire to the opposition.

Steps

1. Ensure that you are near a player on the other team. Diving with nobody around will, at best, make you look like an imbecile.
2. Time your dive. While one could dive with no contact, it is very difficult to make it look realistic. Diving is better used to emphasise a real challenge, making a legal tackle look illegal, then it is to make no challenge look like a foul.
3. Go to ground. You want to throw yourself at the ground, in whatever manner you choose. However, ensure that it is consistent with the type of foul you are simulating. If you are faking a trip from behind, sprawl out forward. For a shoulder-to-shoulder challenge, fall sideways. To show a shirt-tug from behind, fall on your bottom.
4. Fake an injury. This is where you get to emulate the professionals, holding your leg and rolling around in pain. Again, be sure the faked injury is consistent with the foul and the fall. For a slide tackle from behind, hold your leg, to fake an elbow to the face, grab your nose.
5. When the referee takes whatever actions he deems necessary, get up, limp for a few minutes (if you faked a leg injury) and get back into the game.

Tips

• Practice simulating various types of challenges very thoroughly before ever trying it on the field in front of a referee.
• Experience with acting or theatre will serve you well.
• Watch the Italian, Argentinian, Portuguese and Brazilian national teams. They consistently field teams with numerous players capable of executing very realistic dives and with miraculous powers of recovery.
• If the referee does not stop play after your dive, don't press the issue. Chances are he realized it was a dive. Arguing with the referee about a foul he knows was fake is a bad idea.

Warnings

• Simulation is considered unsporting behaviour, and is punishable by a yellow card if the referee spots it.
• Diving may fool the referees, but it will most likely not fool the other players. Especially if a player is sent-off for your dive, you may find yourself receiving a true brutal foul.
• Diving is cheap. It ruins the spirit of the game and destroys the sense of fair play in soccer.
• Some refs will card you for diving because of the poor spirit of it.
• It is also possible to get injured while diving which is simply a very bad case of irony.

Things You'll Need

• a soccer game
• opposition players
• a referee
• no sense of fair play

There's even a video of a team practising diving!