Here's a new foraging link -- a free e-book about acorns, a wild edible found readily across North America.
You'll find out almost everything you want to know about preserving food here at the National Center for Home Food Preservation.
This was by far one of the most intriguing (and potentially dangerous) things I've come across in a while. I've only glanced through it. It's a .pdf guide about practicing medicine in austere conditions where appropriate technology and professional assistance are unavailable. (I'm no medical expert, so I'm certainly not recommending any of the info in that guide, which is full of disclaimers itself.)
Then there's Howtopedia -- the Wikipedia of practical skills, where users are invited to write articles to contribute to this self-described practical knowledge library.
Finally, here's a simple guide on how to make homemade cider vinegar.