eXtrudy was just introduced to the Android Store. It's a completely free application which will allow you to easily turn pictures or drawings into 3D printable 3d models. The app was just ported over from Windows. The creator is not trying to make a profit from it, and intends to hopefully port eXtrudy over to iOS devices soon. More details on this app can be found here: http://3dprint.com/14521/extrudy-android-3d-app/

Below is an example of a 3D print created from an eXtrudy model: