3D drawing: SketchUp
by The EditorSketchUp by Google is a cross platform 3D drawing program for Mac OS X and Windows and comes in both a free and commercial version.
From Google SketchUp website:
Google SketchUp (free) is an easy-to-learn 3D modeling program that enables you to explore the world in 3D. With just a few simple tools, you can create 3D models of houses, sheds, decks, home additions, woodworking projects - even space ships. And once you’ve built your models, you can place them in Google Earth, post them to the 3D Warehouse, or print hard copies.
Google SketchUp is free for personal use. No registration is required.
SketchUp Pro 5 is a powerful 3D modeling tool whose robust feature set empowers design professionals to explore and communicate complex concepts, import and export a host of file formats, and create interactive presentations. You can also use SketchUp Pro to print to high-resolution devices, place your models in Google Earth, and post them to the 3D Warehouse.

