Nintendo finally has an official website for this game. http://www.smashbros.com/us/
And as you can see, there will be Megaman in this game! I wish it was Megaman X (cause he's cooler and looks more kick donkey), but Megaman is still gonna be a great addition to the Smash Bros lineup!
Two other newcomers have also been mentioned. One is the Fitness Trainer from Wii Fitness, the other is someone just called Villager and I have no clue what game he's from.