A flipturn is a type of turn a swimmer does in order to get to the other end of the pool, thus accumilating the necessary distance in order to finish the event. The flipturn is only necessary in an even that is longer than one lap of the pool. This turn in used in freestyle and a modified version in backstroke. The technique for each turn is essentially the same, the only difference is the approach and the pushoff.

The Approach
This is different in freestyle and backstroke. For starters, on is done on the back, the other one is done on the front, otherwise, the flipturn is the same.
The Initial Position
Is on the chest, approximately two feet away from the wall, facing the wall. One arm is extended in the recovery position, the other arm down the side of the swimmer. It is assumed that the last breath has been taken bofre this position, otherwise, it is very easy to get water up your nose, and possibly even drown....not fun stuff.
The Beginning
This starts by the recovery arm, beginning a normal pull, the head follows the arm in this case. As the arm passes the shoulders, the swimmer tucks his/her chin into their chest. While the recovery arm is proceeding to pull towards the swimmer's hips, the shouldars are submergerd deeper, allowing the swimmer's center of gravity to stay at a relatively constant distance from the wall.
The Flip
The hips are brought over the center of gravity, bringing the legs out of the water, and allowing the feet to come in contact with the wall. The trick here is to know the distance from the wall, in order not to smack one's heels on the deck, but still be close enough to the wall for an effective push-off. This is achieved through repetition, and repetition only. Sometimes I allow myself to look back at the wall (because my chin is tucked into my chest, I sometimes can see the wall, and thus be a better judge of the distance to the wall, imroving on the flipturn).
The Crouching Swimmer
Here the swimmer is on his/her back, feet against the wall, arms out in a streemline. If you'd look down on them from the edge of the pool, it allmost looks they're doing sit-ups, with their arms straight in the air and on the balls of their feet. Sometimes, a slight twist can be noticed to the swimmer's bodies. However this does nothing to improve the time on the wall, it does, however, improve the turnover, where the swimer must flip back onto his/her stomach if doing freestyle. This twist is achieved in the previous stage of the flipturn, where the hips are brought over the center of gravity. There, the hips are turned slightly, putting the feet at an angle to the vertical, depending on which way the swimmer will be turning over later.
The Push-Off
This stage is simple, the swimmer simply pushes off the wall, and depending if the swimmer is doing freestyle or backstroke, he/she turns over on the stomach (in the freestyle case) with aid of the kick, and the first stroke.
Its that simple. However, this should not be perfomed by inexperienced swimmers, injury can occur when distance to the wall is not judged correctly, and heels of the feet strike the wall. Practice this only under close supervision of a trained proffessional, never alone if you are attempting the flipturn for the first time.

Also, there is a new type of turn in the breaststroke. It looks somewhat like the flipturn here, and also like the traditional open turn, Im not sure what its called, but as soon as I find out, I shall create a node for it.