RoboCup
In one of the conferences that I attended during ITURO2010, i listened about RoboCup. After a little search in the internet i learned the basic rules and start working on a small size league team in theoretically. RoboCup is an international robotics competition founded in 1997. There are three main branches under the name of RoboCup, these are "Robot Soccer World Cup", "Search and Rescue", and "Robot Dancing". The main goal of this organization is to build fully autonomous robots to play against FIFA 2050 World Cup winner and win the game.
There are 5 different leagues under RoboCup Soccer. I'll briefly talk about the other 4 and try to explain the rules of SSL by drawings. FIFA soccer rules are applied in the leagues of course with some modifications.
RoboCup Simulation League
There is no actual robots on this league, it all simulations. Each half being 5 minutes in duration and the game lasts 10 minutes. Each simulated soccer playing robot may have its own play strategy and characteristic and every simulated team actually consists of a collection of programs.
Humanoid League
In this league, autonomous robots with a human-like body plan and human-like senses play soccer against each other. In addition to soccer competitions technical challenges take place. The robots are divided into two size classes: KidSize (30-60cm height) and TeenSize (100-160cm height). Dynamic walking, running, and kicking the ball while maintaining balance, visual perception of the ball, other players, and the field, self-localization, and team play are among the many research issues investigated in the Humanoid League. Several of the best autonomous humanoid robots in the world compete in this league.
The RoboCup Standard Platform League (SPL)
SPL is soccer playing standardized robots. From 1999 to 2006 Sony Aibo's are used in the league, after Sony stop the production of Aibo's the league moved to a new platform Alderan Robotics humanoid NAO. 
The RoboCup Middle Size League (MSL)
Five fully autonomous mid sized robots with all sensors and wireless communication devices (if any) on board play soccer. The robots may communicate by means of a WLAN satisfying IEEE 802.11 specification. There is no human contact with the robots. FIFA standard size 5 orange ball is used in the games. The field dimensions are 12 m x 18 m.
*The goal keeper can increase its dimensions temporarily to 600x600x800 or 500x500x900 for 1 second. After returning back to its orginial size it has to wait 4 seconds before expanding again.
*All dimensions in mm
The RoboCup Small Size League (SSL)
SSL is the smallest one of the phisically soccer playing robots in RoboCup. There are five robots on the pitch and there is a over head camera 4m above the center point. The broadcasted video footage send to a computer and the computer is in contact with the robots in the fields wirelessly.
*All dimensions in mm
Dimensions of the field is specified, also the other dimensions like penalty mark, center line. Although the surface material of the pitch is not given.
There are 250 mm empty space with the same color of the field from both sides and 100mm tall walls will prevent the ball and robots from running off the edge. Behind the walls there are 425mm empty space is designated referee walking area. All lines are 10 mm wide and painted white. The penalty mark is a 10 mm diameter circle of white paint.
The inner face of the goal has to be covered with an energy absorbing material such as foam to help absorb ball impacts and lessen the speed of deflections. The goal walls, edges, and tops are white in color. The floor inside the goal is the same as the rest of the playing surface.
One of the most important mechanisms in the robots is dribbling mechanism. This mechanism helps the robot to control the ball. 20% of the ball can be covered by the robot while holding the ball. A robot is holding a ball if it takes full control of the ball by removing all of its degrees of freedom; typically, fixing a ball to the body or surrounding a ball using the body to prevent access by others. 80% of the area of the ball when viewed from above should be outside the convex hull around the robot. Another robot must be able to remove the ball from a robot with the ball.
The ball is a standard golf ball, orange in color. 
If you look from the top of the field. The ball and the robots will look like this.
Autocad Drawings of Pitch, Goal, and Robot
