What is the name of that iPhone app that can change the look of your other apps?
The way you say that you're not crazy suggests you've asked other people before and they've told you you're crazy? Anyway, it could just be under iPhone settings or something, otherwise I don't know sorry.
Your iphone has to be jailbroken
That's called CocoPPA, but you can't delete the original app, you will have to hide it in a folder. The instructions for putting the icon are in the app, I believe.