Street Fighter and Tekken fighters will go head to head with each other in two games...

Street Fighter X Tekken:
2D Game
Tag Mode Confirmed
Developed by Capcom
Ryu, Kazuya, Chun Li and Nina Williams confirmed (by Trailer)

Tekken X Street Fighter:
3D Game
Developed by Namco

I personally can't wait for more information! Keep in contact with Tekken Nation for the latest information on both games.