First of all, let me say that this is an absolute no brainer. (Except to all you grid iron fans in the US apparently)
From:
http://worldsoccer.about.com/cs/worldcup/a/wcupnews.htm
we see that the total viewership for the 2002 World Cup was 28.8 billion. There were 64 games at the World Cup giving an average of 450million viewers per match.
The statistics from
http://www.nielsenmedia.com/.../WorldCup_Final.htm
were not indicative of total global viewership, as it clearly states that the only countries included in the survey were:
Australia, Canada, China, Finland, Hong Kong, India, Indonesia, Ireland, Malaysia, New Zealand, Philippines, Singapore, South Africa, South Korea, Sweden, Taiwan, Thailand and the United States.
Taking into account that most of the largest football viewing markets in the world, such as Brazil, Argentina, Great Britain, France, Germany, Italy, Spain, Portugal, as well as the rest of Latin America and most of Africa and the Middle East, were excluded from this survey, the actual number of viewers of Wordl Cup matches would definitely greatly exceed the numbers stated in the survey.
Also, the statistics from:
http://www.forbes.com/.../0527fifa.html
show the number of viewers for the 2001 NBA Playoffs and Finals to be 2.5 billion. The 2.5 Billion people as stated here watched a total of 71 games in that year's playoffs and finals, compared with 1 billion for a single match at the 1998 world cup.
The fact remains that the Football World Cup is viewed by a much larger audience than the SuperBowl.