The arcade sports hit is being revived for 3DS.
http://www.nintendoworldreport.com/news/27762
Mario Tennis will be released on Nintendo 3DS, Nintendo announced at the 3DS conference in Japan. The game will be released in 2012, and will feature optional gyroscope control.
The video showed at the conference spotlighted Mario, Luigi, Peach, and Bowser playing tennis together. Although it is unknown who is developing the title, the previous Mario Tennis games on Nintendo 64, Gamecube, and Game Boy systems were developed by Camelot.