Hi guys!, I need help with edges in minecraft. They aren't smooth just look at this http://fotoo.pl//out.php/i112807_2012-0 ... .59.41.png

These edges are so ugly, could you tell me what i should do to fix them? I know it's possible cause people on youtube have smooth.
My GPU is ATI Radeon 6850 HD. Please help, ( And sorry for my english )