There is a roundabout to get cell shading in Unity iPhone or any other 3D environment, without the need of using the real and useful and smart shader.
If we analise the main concept, to get cell shading you need:
- soft shadowing and a bit flat - undetailed textures
- a pen line (mainly black) surrounding the shape of the 3D model.
The first key point is easy to achieve: texture and light work to get the toonish look, not too dark shadows, but nice if there is a noticeable contrast between lighted and shadowed.
The line stuff, that may be harder to achieve, is "easy" if you get you 3D model, make a copy of it, scale it a bit and flip the normals. Then apply a black material on it, and you have your line.