I would chime in on checking books out of the library. If your library doesn't have them, ask your librarian about borrowing them through interlibrary loan. You might also be able to get magazines from there, depending on what subscriptions they have.
I've learned a lot by reading through posts on this forum. I think the stickies about the super foods are really good. There are also some great resources on the web, like the world's healthiest foods,
http://www.whfoods.org/
and the Harvard food pyramid
http://www.hsph.harvard.edu/nutritio.../pyramids.html
As far as where specifically to get started, if you're looking to make changes for the whole family, you might want to pick one or two areas to start with. Things like serving more salads, or beginning a switch to whole grains, for example, could be a good start. It sort of depends on where you all are with your eating right now, what everyone's comfort level is, and what kind of foods you think people will enjoy trying or wouldn't mind giving up. For a lot of families a gradual approach works well because it's not too overwhelming.