dunno, Ive always used the various tutorials and help in the program itself
there's alot to learn, plus you will probably find yourself making 3D objects for scenes using other apps instead, it really isnt all that great at 3D design, its better at animation/rendering really, good control over object positions and lighting and dynamics of objects colliding, plus you use scripts to move things around for frame by frame animation
if you wanna see what it can do, google for or see this:
http://orange.blender.org/
its a short film using blender mostly, its all 100% opensource including the scripts and techniques they used