Roger Federer has won four Australian Open titles so far. He lifted the Norman Brookes Challenge Cup in 2004, 2006, 2007, 2010, tying him with Andre Agassi as the winner of most Men's Singles titles. Federer has been runner-up once in 2008, where he was beaten by Rafael Nadal in 5 sets. Most people will probably remember this final because of Roger's tears at the trophy ceremony (I still can't watch the ceremony...emotional

) .
Here's the stats from Federer's wins.
2004.......
Australian Open
(1).......Marat Safin (RUS).................7-6, 6-4, 6-2
2006.......
Australian Open
(2).......Marcos Baghdatis (CYP).......5-7, 7-5, 6-0, 6-2
2007.......
Australian Open
(3).......Fernando Gonzalez (CHI)......7-6, 6-4, 6-4
2010.......
Australian Open
(4).......Andy Murray (GBR)...............6-3, 6-4, 7-6
Federer with the trophy at the 2010 Australian Open.
"In an era of specialists, you're either a clay court specialist, a grass court specialist, a hard court specialist....or you're Roger Federer."
-Jimmy Connors