Saltpeter is the oxidizing agent in gunpowder, a major component for war tools like guns and bombs. (Stay with me, I do have a point.)
For a thousand years or so, people made saltpeter out of wood ashes and various combinations of poo and pee, bat guano being the best. Basically, if you wanted to wage war, you have to have bat shit.
Germany, itching to start a little conflict we now call WWI, found itself in a jam because the Brits owned all the bat shit. Along comes a smart German scientist named Haber who invents a method to create synthetic saltpeter. Suddenly an unlimited supply of domestically produced gunpowder, yadda yadda yadda, millions of lives lost and some British investors found their oversees bat cave investments worthless.
The point is that we have a lot in common with early 20th century Germany:
1) a much-needed natural resource
2) that resource is owned by a foreign gov't hostile to our interests
3) some damn smart domestic scientists
4) a whole pile of money and a national can-do attitude
Ladies and gentlemen, oil isn't going to disappear one day like turning off a light switch. It will gradually get more expensive, which will spur investment into alternative energy sources.
We have already seen an economic shift of gigantic magnitude. GM is out of business because nobody buys domestic SUV's anymore, they all buy foreign hybrids.
I don't know what the answer will be. Maybe we will be shoving ears of corn into our gas tanks, maybe cow farts, maybe solar or wind or Mr. Fusion. Who knows.
Relax, and let our wonderful free market take care of this problem. We only need to be careful not to stifle this innovation.