Atlus have two Naruto Shippuden games releasing this year: Dragon Blade Chronicles on the Wii and Naruto vs. Sasuke on the Nintendo DS. Both have multiplayer modes, too.
Dragon Blade Chronicles multiplayer looks like a regular 3D arena fighter:
Meanwhile, Naruto vs. Sasuke looks a little reminiscent of the Super Smash Bros. style:
Both games are releasing this month on November 16th. Atlus have a third Naruto Shippuden game, Naruto Shippuden: Shinobi Rumble, scheduled for February 8th, 2011.