Comic Book Movie got their hands on an Avengers movie tie-in storybook, and they've published most of it. Or the version they have doesn't have the whole movie, as it stops about halfway through the film's story. So don't worry too much about huge, major crazy spoilers.
I like the way the storybook brings over some of that Whedonesque feeling of great dialogue and character interplay. And my favorite image from the storybook is above, of Cap in ice, from the film's prologue.