Licorice Root (available via Herb-Pharm, Whole Foods, or your local health food store for about $11/oz.) is said to inactivate the herpes virus.
Internally, I took a dropper full of Licorice Root orally under my tongue once a day for about 3 months with zero noticeable affect.
WARNING: Licorice Root can raise your blood pressure to deadly levels. I’d even be cautious with deglycerinized licorice.
Topically, I believe Licorice Root is probably about as close to a cure for Herpes as you can get. I have a small spray bottle that I keep in my bathroom and I spray my groin region and rub it in when there are signs of outbreak or shedding (slightly pink areas, itching, etc.). Since the virus will attempt to go around it, it is best to spray and work it into the entire region.
Update: I believe there is a synergistic effect when Licorice Root is used with Tea Tree Oil. The combination appear to work better than either one by themselves. The Tea Tree Oil has a sort of menthol effect of keeping the pores open so that the Licorice Root can be absorbed.
Update 11/1/07: See Current Experiements