One of my favorite treasures I've found via AmblesideOnline.org is the great books available online FREE from the Baldwin Project.
The Gutenburg Project, www.gutenburg.org, is a project that scans copyright free books, which means older books, and making them available online. This is great, but the plain text and no illustrations leaves me a bit cold. Admirable project though.
The Baldwin Project, www.mainlesson.com, took it a step forward and the books pop up on a yellow background which I find pleasant, large font size my son can read, and great illustrations incorporated. I'm in love with the books there! Some of the books are available to purchase, but never fear the full text is still available online.