White has been in Europe for the past two seasons, playing in Italy with Dinamo Sassari and VL Pesaro. In 2010-11, White was the leading scorer in Serie A when he averaged 20.2 points per game.
Our Knicks blog, Posting and Toasting, has a nice summary of White and what he brings to the table:
You might be wondering who James White is. Well, he's a 6'7" small forward and you probably remember him best from the high school dunk contest he unjustly lost to David Lee. When he was in the league, that was really his thing-- jumping very high and dunking a lot-- and he struggled to do much else.
Whether White is just a summer camp body or actually will get a guaranteed contract is still unknown, but odds are his playing time (if he has any) will be extremely limited.