Check it out at: http://doit.im/gtd.jsp
Use graphics you create in Livebrush within your existing projects. Create entire compositions in Livebrush alone. Share styles and see how others combine your brush with their ideas. Give it a try, or learn more.
Yep, Photoshop on the iPhone. At first glance, it's not much different from other light iPhone photo editing apps, except that it's tied to their online service, but the effects and interface look above average.