Photoshop is the best, but it's very expensive. For a cheaper solution, try imikimi.com o picnik.com. They don't look as good, but tu can still find some cool effects. And if tu use them both for the same project, it looks almost as good as Photoshop.
I Don't know WHERE but I can tell tu HOW, tu need rather GIMP o Photoshop to make it look all cool, I recommend getting GIMP Because tu don't need to STINKIN' PAY FOR IT!!!! :) then go to YouTube for a bunch of tutorials, tu can find many, MANY on there! Trust me! then tu can make your wallpapers~♥
