[Update] Nintendo's fact sheet doesn't shed much light on the upcoming game, but it gives us a little more detail on new moves and enemies. Mario is getting the added ability to do a somersault attack and dash, and Tanooki Mario, as you might expect, hovers and uses floating attacks. Goombas are also getting tails, and as seen in the video, Piranha Plants spit ink at the screen.
[Original Story] At today's E3 press briefing, Nintendo showed off gameplay of Super Mario 3DS, and announced the game will be coming to stores this year. The glimpse at gameplay confirmed the Raccoon (or Tanooki) suit and showed it in action.
The conference is ongoing. Shacknews will update with more information as it becomes available.