Sony have announced Everybody's Tennis for the PSP. this game currently has a late June 2010 release date. Everybody's Tennis features highly customisable characters, with over 500 items to choose from. The game also features 4 player game sharing multiplayer.
each new area in the games story mode will come with tasks to complete before you are invited on court to play against the areas best players. each court in the game also has its own physics to understand and to choose the best shots on. As you progress, the difficulty increases whilst the competition becomes more unusual. there are even some hidden objects to collect on the courts to help characters progress.
Screenshots
From EU Playstation Blog