Disney, from Ruffles and Stuff has a really easy tutorial on how to make the same thing.
Now for the pants. I originally bought these "jeggings" at Walmart for $1. I bought 2 because I just can't resist the urge to buy clothing when it is discounted to a DOLLAR! Anywho, I took an existing pair of leggings (of Amaree's) and used it as my pattern. I wanted the zippers to be on her leggings as well so I matched the bottoms of the jeggings and the leggings, then cut. I will have to make a tutorial or find a good one to put on my blog for reference:) I haven't tried them on her so hopefully they fit! If not, I have already gotten my moneys worth (I wore them three times before the crotch ripped).
Have a wonderful day!