Here are some Prince of Tennis Games that you can play with Emulators.

Visual Boy Advance (GBA-Emulator in case you don't have one) [soon]

Minnaouji (not sure whether it's the real title)
http://www.megaupload.com/?d=9D899JMZ
Tennis no Ouji-sama 2003 - Cool Blue [soon]

Tennis no Ouji-sama 2003 - Passion Red [soon]

Tennis no Ouji-sama 2004 - Glorious Gold [soon]

Tennis no Ouji-sama 2004 - Stylish Silver [soon]

Tennis no Ouji-sama - Aim at the Victory! [soon]

Tennis no Ouji-sama - Genius Boys Academy [soon]