I have been an avid "backpacker" since the late '60s, long before somebody invented the term "backpacking" or made it a marketing buzzword. As far as I knew, it was just the way Scouts went camping, and I loved it. I still do, although having a wife, three kids, two jobs, and two motorcycles have made it hard to find time to get out in the wild lately. I suppose the high point of summers while I was in high school was the two-week trips to the gold country in the Sierra Nevadas with a bunch of Explorers.
We would form groups ("crews") of five or so, load up enough food for a week, then spend that week going from body of water to body of water, visiting old gold mines along the way. We would then resupply somewhere near a road, eat some real food, then head out for another week. The trips taught me that I could do a lot more than I thought, that there were still places roads didn't lead to, and that you could eat well on a backbacking trip without buying expensive food from a sporting goods store. Most of what we ate was available from grocery stores, or from institutional food sources like Bernard's (who supplied the area's Scout camp).
The two top leaders were Dick Hacke, a Scout administrator who lived and breathing Scouting and the outdoors, and Jerry "Bull of the Woods" Barndt. They were supported by a number of college-age guys who had made the trip for years. Although the leaders are probably different by now, I would bet the hike is still going. Only now do I, a working stiff with two weeks of leave per year, realize what a big deal it was for the leaders to spend two weeks making the trip possible.
Campmor catalog of all sorts of camping equipment.
Backpacker magazine, a wonderful resource for places to hike and pack into, very good reviews of equipment, and lots of other reading to keep your interest in backpacking alive and well, especially through the winter.
National Parks Foundation. A guide to America's National Parks. Cross-indexed by name, state, region, special interest, etc.
National Parks Service Trails. A surprising number of links to parks that have special pages for trails. Also a link to their page of links for general information on the many National Parks.
The Mining Co's camping page. A zillion links to all things about camping.
GORP A clever acronym for Great Outdoor Recreation Pages. Parks, forests, wilderness.