Yao Ming has scheduled a press conference for July 20th in his hometown of Shanghai, where he will officially announce his retirement from the NBA. As an unrestricted free agent, Yao is under no obligation to the NBA or the Rockets -- he can simply walk away from the game. His tremendous impact on the NBA can hardly be measured, as international interest in the game has exploded in recent years. Even below-the-radar Rockets big man Chuck Hayes is currently on a promotional tour of China.