Getting children to read, read, read is vital. Shop in used book stores if need be. Parents need to be aware of the subtle way ideas are passed on to students. A careful reading of National Geographic or the newly written exhibit descriptions at the Smithsonian Museum will give you a clue to the depth of this indoctrination.
Very true that homeschooling is not an option for everyone (and not an easy one for those of us who have undertaken it!).
However, I think it's very important for parents to be aware of what their children are being taught so that they can flesh it out at the least, and counter it if need be. Homeschooling materials can be very helpful for this (personally, I like the guidance given in the classical education guide, The Well-Trained Mind, and their website, welltrainedmind.com. They offer guidance not only for homeschoolers, but also for parents seeking to enhance their children's public school education, as well as for adults who are in the process of self-educating).
CW has got the key...."read, read, read"...and reading as a family is the best. You can't start kids enjoying books too soon (nor adults too late!).