David Graham in 1981. Geoff Oglivy is the other Australian to have won the U.S. Open, that being in 2006.
Maria Sharapova won the Australian Open in 2008.
No, Kim Clijsters did not win the Australian Open in 2003. She won the Australian Open in Women's singles in 2011. She did make it to the Quarterfinals in Doubles at the 2003 Australian Open. Serena Williams won the Australian Open in 2003 beating her sister Venus Williams in the final.
Chris O'Neil in 1978.
Peter Finch was the first Australian to win best actor (although born in England) Geoffery Rush was the first Australian born actor to win best actor.
Yes, in 2010 Serena won australian open champion 2010 title.