Believe it or not, there was a food supply before McDonald's. Hard to believe, but true. Not only was there food before the Big Mac, but there was FREE food. And, that food supply still exists. It is right outside your door. If you know which plants are edible and how to prepare them you can survive in the wild.
Here is a wonderful place to start: Sunny Johnson's Wild Food Plants website.
Her site includes short videos that show you what the plants look like, how to harvest them and how to cook them.
Unfortunately, it seems that Sunny has lost her videocamera, so it might be awhile before there are more videos. I hope she gets a new one soon, because I love the ones she has done so far. I'm planning on making False Dandy Balls for next Sunday Brunch.
Here is another lovely site to help you grow your own edible plants: How to landscape with edible plants.
For more sites and books, just search the term "edible plants" in your search engine.
Warning: some plants are poisonous. It is important that any plants that you eat are positively identified and you know they are safe to eat. For more information on how to do this, click here.
Now, go weed and eat.