Here's a good summary from Eurosport of the different disciplines being contested in the cycling category :

http://www.eurosport.co.uk/home/page...to622523.shtml


Cycling at a glance: A short history

Cycling has been an Olympic mainstay since the dawn of the modern Olympic era in 1896. That first Olympic road race -- also in Athens -- traced a relatively short 87 km in comparison to 2004's distance of 239 km for the men's race.

While men have been racing for Olympic gold for over 100 years, the women were only given their first go at the 1984 games in Los Angeles.

1996 was also a boon time in Olympic cycling history with the addition of the time-trial and mountain-bike disciplines for both men and women.

Rules and regulations

For the road and mountain bike events, the rules couldn't be simpler: mass-start races held on tough roundabout circuit courses and won by whoever crosses the line first.

The comprehension of the track events, however, requires a little extra know-how. Here are the general guidelines for the showcase track cycling events:

Time trials: It's all about strength and stamina -- tactics are of no avail in this discipline. The men race for 1,000 meters, the women for 500 meters, the first to pass the finish line wins and advances to the next round.

Sprint: The athletes have to cover three laps in the sprint event, but only the last 200 meters count. On the first two laps, the two opponents jockey through a series of cat-and-mouse tactics, each trying to force the other to launch the final-lap sprint. The rider in second position at the start of the bell lap is considered to have the upper hand, as he/she can then draft -- saving precious energy -- before exploding in the final sprint for the finish.

Individual pursuit: Two riders race at a time, beginning from opposite points on the track. The goal is to catch the other athlete (hence the "pursuit" event name) or at least record the fastest time over a set distance of four kilometres (for men) and three kilometres (for women).

Team pursuit: The race works just like the individual pursuit, but with teams of four taking place. The finishing time for each team is recorded as soon as the third rider crosses the finish line.

Points race: Distance: 40km for men and 25km for women. Points are awarded every ten laps (5 points for 1st position, 3 points for 2nd, 2 points for 3rd, 1 point for 4th, with points doubled in the final sprint). The rider to score the most points during the race wins.

Madison: Named after New York's Madison Square Garden, where the first race of its kind took place. Similar to the points race, points are awarded every 20th lap. Riders compete in teams of two.

Keirin: Originally from Japan, Keirin made its Olympic debut in Sydney in 2000. Two racers each follow a motorbike for 5.5 laps and then compete head-to-head for a remaining 2.5 laps.

Olympic Sprint: Despite its name, this event didn't actually make the Olympics until Sydney in 2000. Two teams of three riders each compete against each other -- much like in a pursuit race. The first team to cross the finish line after three laps wins.

Cycling at the Olympics, Competition dates

Men's Road Race: August 14

Women's Road Race: August 15

Men's Time-Trial: August 18

Women's Time-Trial: August 18

Women's Mountain Bike: August 27

Men's Mountain Bike: August 28

Men's/women's track events: August 20-25


Defending Olympic champions:

Road Race
Men: Jan Ullrich (GER)
Women: Leontien Van Moorsel (NED)

Time-Trial
Men: Viatcheslav Ekimov (RUS)
Women: Leontien Van Moorsel (NED)

Mountain Bike
Men: Miguel Martinez (FRA)
Women: Paola Pezzo (ITA)

Track
Sprint - Men: Marty Nothstein (USA)
Sprint - Women: Felicia Ballanger (FRA)

Individual Pursuit - Men: Robert Bartko (GER)
Individual Pursuit - Women: Leontien Van Moorsel (NED)

Points Race - Men: Juan Llaneras (ESP)
Points Race - Women: Antonella Bellutti (ITA)