Even if you're not an artist, the urge to sketch and doodle strikes us all now and then. If you have an iPhone in your pocket, LiveSketch is one app that's as simple to use as pen and paper -- simpler, actually, as you will see in a moment.
Where many apps (like Paper for the iPad) pride themselves on offering numerous brushes, LiveSketch has just one. Yup, just one, single brush -- and no, you can't unlock others by paying. This single brush automatically creates shading: Put a couple of strokes close together, and they'll become interconnected through a web of tiny, tiny lines.
It sounds complicated, but in practice, it is very easy to grasp. Creating shaded areas and making parts of your work feel "heavier" or thicker is quite simple. The downside is that fine-detail work is nearly impossible: Whenever you try to put a line down, it will often be joined to other lines near it.
LiveSketch comes with a simple color-picker that remembers the last 8 colors you've picked, letting you toggle between them. Apart from the super-basic brush, that's all you get -- but actually, for creating quick sketches, that can be enough. Just let let you imagination run free.