Some examples using "was" IN DIALOG (the writer doesn't think its correct, but wants to show how real people really talk):
"Well, Ben Rogers, if I was as ignorant as you I wouldn't let on."--Mark Twain, "Huckleberry Finn"
"Well," said Joe..., "if I was yourself, Pip, I wouldn't. No, I would not."--Charles Dickens, "Great Expectations"
Some examples using "was" where a famous writer is using it himself (he thinks it's perfectly correct):
"Some of my friends spoke as if I was coming to the woods on purpose to freeze myself."--Henry David Thoreau, "Walden"
"I foresaw that if I was driven into either of those currents, I should be carried a great way out to sea."--Daniel Defoe, "Robinson Crusoe"
"Yet it was evident that if I was to flourish matches with my hands I should have to abandon my firewood."--H. G. Wells, "The TIme Machine"
Some examples using "were," the strictly correct usage:
"Could I see it from the mountains/If I were as tall as they?"--Emily Dickinson
"putting me before the fire as if I were going to be cooked"--Charles Dickens, "Great Expectations" again. Unlike Jo, the voice of the narrator in the book uses "were."
And finally, here is H. L. Mencken bellyaching about the death of the subjunctive in 1921: "All signs of the subjunctive, indeed, seem to be disappearing from vulgar American. One never hears “if I were you,” but always “if I was you” ... Perhaps in another generation the subjunctive forms will have ceased to exist."