On the basis of it being mentioned in Heilemann’s widely-linked Maker of Films post, Michael Rubin is making his book Droidmaker available for free in PDF.
This is likely a limited-time thing, so nab them quickly… Or you can go buy the book, since as I recall it’s pretty hefty – too much so to read the whole thing on a screen. Plus, that’s just the right thing to do… Now I gotta wonder where my copy is. (Probably went into a JadeCon teacup auction, come to think of it…)
UPDATE: Rubin has posted a Droidmaker FAQ.