Microsoft VisualBasic 3.0 Language Reference, which came with VB3, was my bible durring my learning process, but theres obviously a newer version out there somewhere. It was sufficient to teach myself VB6, but sometimes I had to improvise because of changes. Either way, I survived.
Also, I have MS VB3 Programmers Guide, but have yet to read it. I suppose its supposed to teach you coding habits. If so, avoid it
EDIT: Programmers Guide teaches you how to use the IDE. That was a 3 second crash course for me.