One of the first places that I found when I started on my preparedness lifestyle was http://survivalistprepper.net/. Dale, who created the site, is a great guy and has lots of informative data that he has personally written, Dale also has a weekly Podcast on the subject. They have a great community over there of which I am glad to be a part of, so head over and check out the Survivalist Prepper.
Jack Spirco at the Survival podcast has some very level-headed opinions on a wide range of subjects, additionally he has some great guests to the show, I have to credit my start in Bee Keeping to ‘The Bee whisperer’ who was a guest on the show. Heavily in to permaculture and human liberty he is another one of my regular podcast listens. Certainly for the American community the Members Support Brigade offers great discounts. http://www.thesurvivalpodcast.com/
So far as Prepper groups go, the P2S network in the UK differs from the standard Facebook groups of wannabe survivalists and is Website / forum based. The group has being running since 2009 and is strict as to who gets in and once in you have to communicate regularly in the group to have full access within the forums. Its well structured, has good knowledgeable members who can help answer any questions on pretty much any subject. The main site is full of useful data at www.p2snetwork.co.uk