http://analoguechic.com/2011/02/how-to-create-an-inspiration-board/

What is an inspiration board?

An inspiration board is basically a collage of images, words, and objects (fabric, trims, paint chips, packaging, etc.) that a designer has collected and wants to organize and keep at hand as a reference for a project they are working on.
It can be in the form of a paper poster, a bulletin board, a digital graphic, or a video. Really, any visual medium. Papier mache sculpture. I don’t know.
It’s a way to organize your references and research to create a framework for your design.

How is it different from a mood board?

A mood board sets the mood – a style, feeling, emotional scenario, ambience, presence, context—for whatever the final product will be.

For example: Soft or hard? Grungy or clean? Dark or light?

An inspiration board is more specific and visual—a collection of visual references that are the starting point for elements that will eventually show up in the designed product. In this case, there is a more literal connection between what shows up on the inspiration board, and what ends up in the final piece. It would include things like photographs, illustrations, screenshots, color swatches, words, shapes.

So the mood board gathers all the research and images of how the product will make you feel, and an inspiration board gathers all the reference points for what the product will look like. Mood board: woo-woo, conceptual, feeling, psychology. Inspiration board: details, colors, forms, texture, lines.  The mood board should influence what goes onto the inspiration board, and the inspiration board should respond to the mood board.