Literati.me
Here's the pitch: I've been working on iPhone icons here and there for a couple years, and sometimes stuff that looks amazing in Photoshop just didn't sit well on the home screen. I needed a quick way to see it in context, especially when I don't have the code.
So Iconico lets you upload your icon, and besides showing you how it'll look at all the different sizes, gives you a URL that you can install as a bookmark on your homescreen, which magically shows you your icon in context!
Simple & easy.
