Here are some neato vector tutorials:
Figure Shading: when less is more, by Russel Tate. Ever wonder how people use gradients to shade vector illustrations? Because I totally have. A nice explanation by Russel Tate try to ignore the fact it's associated with istock.
From sketch to vector illustration by William Beachy is about Beach's process from sketch to vector illustration. What I think is most useful here is how he uses traditional comic inking "rules" to draw digitally.
Quick Tip: How to Cell Shade and add Texture to a Vector Comic Character is just like the man says.