Swimming is a very physical and demanding sport, with athletes competing over distances of 50 m to 1500 m in the pool. Swimmers are enormous strength and endurance to power themselves through the water, and that the technique perfectly sharpened. In addition to events in the pool, 10 km open water will be contested for the first time the Beijing 2008 Olympic Games for men and women.
Apart from 10 km open water competition, events for the Olympic swimming program takes place in a 50-metre-long swimming pool and include 26 individual and six team relay men and women. These include free, backstroke, breaststroke, butterfly and individual medley style. The team events are the freestyle and medley relays.
Swimming Wikipedia and Wiki links are given bottom of this post

Time Schedule of Aquatics - Swimming Games (olympics 2008) | Dates of Events of Swimming
==> 09th Auguest
Name of the Event :- Men's 400m Individual Medley - Heat
Date of Event :- 09/08/2008
Swimming Start Time : - 18:30
End time :- 18:56
Venue :- National Aquatics Center
Team GB Athletes Competing : Euan Dale, Thomas Haffield