PacSun, Delias, Hot topic, Abercrombie, American Eagle, Hollister, Victoria Secret... just go to the mall & look around, they have them everywhere :) Also, http://funadvice.com/r/14t9guu96bs has loads of cute hoodies.
Wouldn't you just buy one you liked in a size smaller than your normal size?
try polyvore.com toofastonline.com yesstyle.com
But Thr Shud B A Place 4 A Tight One. Yu GEt Me?
Stitches, Garage, Bluenotes
Tillys worked for me.
the kids section