First off, I think this'll be the first game where we actualy get to 'be' Peach (Besides Mario party, but I really don't think that counts). Before, she's just been Mario's damsel in distres. Anyway, I'd like to give a long and comprehensive report, but I really can't. There's not much to say.
Games:
Pretty much anything that mario's been in.
Moves:(Now it gets interesting)
Pan: A classic Mario (future site? shyeah, and mybe monkeys'll fly out of my butt) weapon, its basicly a pan to slap people with, and while she waits for mario to save her, Peach'll make pancakes! This move can be viewed, like many others, on the longer of the 2 SSBMelee footages, at e3.nintendo.com.
Turnip, Turnup, fine, LITTLE PLANT THING: It appears that Peach can pull a root-like thing out of the ground, and throws it (I think i even saw her kick it, but don't quote me on that).
Fighter Stance: It appears that Peache's fighter stance is a little wave of the finger, but we really can't be for sure on that.