I've been debating on whether to learn maya, lightwave, C4D or 3DSM for some time now. All appear to be rather complex and would actually require the usage of a rather large book me thinks. I believe there are video tutorials floating about for each program though which are always visually quite handy. I'm pretty sure I've seen PDF tutorials too, but it's a case of motivating ones self to actually look, something which I've been lacking of late.
Definitely something worth getting into though, I reckon once you're familiar with the interface, you'll be on your way. There's a lot of maths involved too I've been told.:icon_wink: