I take it you're not a big tennis fan?

You have four grand slam events that are the premier tournaments. These have large prize funds for the winners. Some tournaments, such as Wimbledon give the men higher prize money than women, with their reasoning being that the mens competition is much tougher to win and is more popular as a result. Other grand slams such as the US Open offer equal prize money.
There is currently the Australian Open event being played in Melbourne and the womens competition has been very poor thus far with the leading players coasting through matches without any trouble at all. The men by contrast has been much more open with far tougher matches and a number of shock results, with the exception of Roger Federer who has had a relatively untroubled time.