At a retail event today in Japan, Nintendo gave more Star Fox 64 3D details.
The game sports a "64 Mode" and a "3DS Mode". In the 3DS Mode, players can control the spacecraft by using the 3DS' internal gyroscope sensor. That means, moving the 3DS right causes the spacecraft to go right, moving it left causes it to go left, moving it up causes it to go up, and so on.
There is also a Battle Mode that supports up to 4 players, through downloadable local play. All four can play using a single cartridge. There is no online mode.
Players can also take photos of their faces with the the 3DS' internal camera. The pictures are used as icons to denote each player's craft.