The Olympic Village have opened on Sunday. With this opening, the IOC Anti-Doping Rules for the Beijing 2008 Olympic Games enter into force.
There are noteworthy changes in the,

Number of tests
increased from 3,600 in Athens to 4,500 in Beijing, to ensure fair play. As a general rule, all top five finishers plus a further two will be tested. The tests include pre-competition controls, which have proved to be decisive. Of the 4,500 tests, around 700 to 800 will apply to urine EPO detection and 900 will be blood tests.

New elements
Specific new elements of the rules include:

- an athlete may be notified and tested more than once during the same day;
- the fact that athletes who miss a test on two separate occasions during the Games, or on one occasion during the Games plus twice in the 18 months beforehand, will be considered to have committed an anti-doping rule violation;
- possession of any substance from the list of prohibited substances will constitute a violation (previously only a selection from the prohibited list applied).

The period of the Olympic Games is defined as “the period commencing on the date of the opening of the Olympic Village for the Olympic Games”, namely 27 July 2008, up until and including the day of the Closing Ceremony of the Olympic Games on 24 August 2008.

As the ruling body for the Olympic Games, the IOC will delegate the responsibility for implementing doping controls to the Organising Committee for the Olympic Games (BOCOG) and the World Anti-Doping Agency (WADA). They will act under the IOC’s authority. The IOC Medical Commission will be responsible for overseeing all doping control processes on-site, which will be in full compliance with the IOC Anti-Doping Rules, the World Anti-Doping Code and the International Standard for Testing (ISO9001:2000).

The tests will be conducted at 41 doping control stations, 34 located in Beijing and 7 in the co-host cities. All venues will be equipped with a standard doping control station where blood and urine can be collected. The samples will be analysed in a period of between 24 and 72 hours only, depending on the kind of test.

ANTI-DOPING RULES
The International Olympic Committee Anti-Doping Rules
Applicable to the Games of the XXIX Olympiad, Beijing 2008
World Anti-Doping Code
The World Anti-Doping Code

Source : http://www.olympic.org/uk/news/olympic_news/full_story_uk.asp?id=2653