@snood,
It's obnoxiously complicated. If I remember correctly, the women have to play the slams, the next big four and five of six of the next biggest tournaments. Then they can fill out the rest of their sixteen slots with their best remaining tournaments. If they fail to do one of the mandatory tournaments, they take a zero even if there are other tournaments they played. (Before the French I think Serena had three zeros and Sharapova had one. Azarenka didn't have any but complained about the schedule overworking her and presenting a health risk to which Sharapova said something like she would never put points ahead of health. Serena will always take a zero over Indian Wells and often blows off Beijing.)
The points for the tournaments are
here. Since Williams dropped early last year she isn't defending a lot of points and will move up to four after Wimbledon. Sharapova will lose out because she had a lot of points to defend and lost relatively early so she's going to lose the number one ranking, maybe falling to three. Kitova (last year's champion) loses big by going out in the quarters and Stosur loses early as well. Had Azarenka won vs Serena she would be a well deserved number one and might be anyway. If Radwanska wins in the final she would take over number one (and if she defeats Serena at Wimbledon everyone would go along with that except maybe Azarenka who has owned her this year.) If Serena wins Azarenka becomes one again.
1 Maria Sharapova 6540
2 Victoria Azarenka 6045
3 Agnieszka Radwanska 7230
4 Petra Kvitova6775
5 Samantha Stosur 6100
6 Serena Williams USA 5640
