Yes, it used to be only available at health food stores, but I see it all of the time in regular grocery stores now.
I would never never say that "this one thing will work for you!" because everyone's bodies are different, but the stuff is inexpensive enough that if it doesn't work for you, it certainly won't break you, and it's just a different form of vitamin C (that has never given me any sort of digestive problems regardless of dose), which is a water soluble vitamin, so there isn't any harm in taking it. It comes in several different flavors, my favorite is tangerine and DBF's favorite is raspberry. I would also suggest using 2 packets to about 8-10 oz. of water, which is less water than they tell you to use in the directions, it tastes MUCH better that way...almost everyone I know does this :)
I've had herpes for 16 years now, and still get OB's when I'm stressed, which happens often. Lysine has helped me, but I hate taking pills. Famvir has also worked well, but you need a scrip and it's hard on the liver. When I start to feel prodrome, I take several packets of the Emergen'C, and about 1/3 the time that wards off an OB altogether, but the OB's always clear up within 2 days.
Again, this is just my experience, your mileage may vary.