The game is a strategy role playing game in which the following characters team up for fight scenes:
Capcom: Ryu & Ken (Street Fighter), X and Zero (Mega Man X), Demitri and Dante (Darkstalkers and Devil May Cry), and Chris and Jill (Resident Evil)
SEGA: Shinguji Sakura and Ogami Ichiro (Sakura Wars), Pai and Akira (Virtua Fighter), Kurt and Riela (Valkyria Chronicles), and Ulala and Touma (Space Channel 5 and Shining Force EXA)
Namco Bandai: Sanger Somvold (Super Robot Wars), Jin and Ling Xiaoyu (Tekken), Kos-Mos and T-elos (Xenosaga), Yuri and Tear (or Estelle... or someone) (Tales of the Abyss), and Kite and Black Rose (.hack)
Andriasang also notes that a trailer is slated to appear later this month. Meanwhile, magazine scans giving us the first look of the game can be found at Nintendo Everything.
As for whether the West will get this one or not? Well, we didn't have any luck with the last such game, Namco X Capcom, but stranger things have happened. Stay tuned.
Update: Here's the full page featuring X and Zero:
Thanks to Maverick-Jin for providing the X and Zero image and scan.