3DCrafter is described as '(formerly 3D Canvas) is a real-time 3D modeling and animation tool that incorporates an intuitive drag-and-drop approach to 3D modeling' and is an app in the Photos & Graphics category. There are more than 50 alternatives to 3DCrafter for a variety of platforms, including Windows, Mac, Linux, iPad and iPhone. The best alternative is Blender, which is both free and Open Source. Other great apps like 3DCrafter are Autodesk Maya (Paid), Wings 3D (Free, Open Source), Autodesk 3ds Max (Paid) and ZBrush (Paid).
VoidWorld is a 3D modeling and animation tool. It provides a wide range of tools. The down load includes a few sample models and an online book which combines the user reference and tutorial examples, that would get you started quickly.
PloppSL allows you to create intriguing Sculpted Prims for SecondLife™ easily. Both texture and model are created in one step. Simply paint the front and back side of your model and it will be converted to a Sculpted Prim by PloppSL.