The matches have yet to be played for 2009. If you are asking about the 2008 singles champion, that would be Roger Federer and Serena Williams.
Roger Federer won the Men's singles title of 2009 French Open.
Serena Williams won the 2009 Australian Open Women's Singles title. She defeated Dinara Safina in the final. This was Serena Williams' fourth Australian Open Singles title.
Roger Federer
Kim Clijsters
Roger Federer
Nadal won the men's singles against Federer and Serena Won the women's against Safina
Juan Martin Del Potro
Kim Clijsters
The Women's Singles title was won by Kim Clijsters at the 2011 Australian Open.
No, he hasn't won any championship this year since winning the Australian Open (2009) Boys' Singles title.
Men - Juan Martin Del PotroWomen - Kim Clijsters
Serena Williams won the 2009 Wimbledon Women's Singles title. She defeated Venus Williams in the final. This was Serena Williams' third Wimbledon Singles title.