The Wayback Machine - https://web.archive.org/web/20071011144942/http://fifa.com:80/flash/lotg/football/en/Laws1_04.htm
Law 1 - The Field of Play
Goals
 
  • Goals must be placed on the centre of each goal line.

  • They consist of two upright posts equidistant from the corner flagposts and joined at the top by a horizontal crossbar.

  • The distance between the posts is 7.32 m (8 yds) and the distance from the lower edge of the crossbar to the ground is 2.44 m (8 ft).

  • Both goalposts and the crossbar have the same width and depth, which do not exceed 12 cm (5 ins). The goal lines are the same width as that of the goalposts and the crossbar. Nets may be attached to the goals and the ground behind the goal, provided that they are properly supported and do not interfere with the goalkeeper.

  • The goalposts and crossbars must be white.

more on The Field of Play