This is irrlevant for the A.T., but for those of you who occassionally head out West to hike, you'll have to adjust to altitude at some point. After a week hiking in Colorado, I can tell you first hand that Diamox (acetazolamide) WORKS. Diamox is a prescription drug which helps your body adjust to rapid ascents in altitude.
I live at sea level and have experienced symptoms of altitude sickness at 5,000 to 6,000 feet. This time I used Diamox and experienced no altitude sickness except for mild fatigue the third day, on this schedule:
DAY ONE: Flew from sea level to Colorado Springs (over 6,000 feet)
DAY TWO: To Gunnison (7,700 feet)
DAY THREE: Started at the trailhead in the West Elk Wilderness at between 8,000 and 9,000 feet.
DAY FOUR: Crossed Storm Pass at 12,600 feet, then descended to about 9,500 feet.
REST OF TRIP: Between 9,000 and 10,500
It's not hard to get a prescription. I called my eye doctor (opthemologist), told him I was going hiking at high altitudes in Cololrado, faxed him some literature on the drug and he wrote me a week's prescription. Here's a good link: