"Inkscape for dummies" has not been published yet, so I hop someone on this list will have an answer.
I would really love to see that, but it seems that the manual will have to wait for the interface to stabalize.
I'm facing a small issue with imported images. For vectorization purposes, I import some small square images and then position them on the canvas. In order to have a good accuracy, I use grid snapping. And here is the problem : I always face a 1.25 coefficient between dimension of the images and grid spacing. Ex 590*590 px images -> 472*472 pt grid 400*400 -> 320*320
You have also encountered my personal favorite gripe. The unit used internally by inkscape is not a pixel or a point it is an SVG user unit. You are probably more familiar with 72 units per inch but the user unit in Inkscape is 90 units to an inch. 90/72 = 1.25
Hope that helps, Aaron Spike