I do a good bit of food preserving here at home - canning, freezing, and dehydrating. I love love love the Ball Blue Book - it's good information, safety tested, and easy to read and understand.
I just came across this online, and wanted to share. The University of Georgia Extension offers a free self-study in home canning. I know that a lot of people want to learn this, so here is the link if you're interested.
Did I mention? It's free!!!
Free Home Canning Self-Study