Undecided Question

What websites can I go to to look at prom dresses?

Even though prom is a few months away, I like to be ahead of everything. :)
I'm looking for something that is classy, but can still make heads turn. I don't want too much skin showing, but I don't want to completely cover myself up either. I don't care if the dress is long or short, I'm just not trying to spend over $300.

If it helps any, I'm 5'5" and a size 3.
http://26.media.tumblr0o0com/tumblr_kxwczryKdm1qaktmao1_250.jpg
^^ I promise I'm not this awkward looking in person. At least I hope not.