Our Dr. Golob says that lolo's homemade solution (in comments over here) will work just dandy:

I mixed 1 part dishwashing soap with 2 parts rubbing alcohol and it seems like it's close to the same stuff...

Apparently good old rubbing alcohol alone would be good enough, but it evaporates too fast: You need 10 seconds of wetness for it to work.

Purell's current tagline: "IMAGINE A TOUCHABLE WORLD." (Their website also happens to have a $2 coupon.) Surely Slog can do better for the tagline for Lolo's Homemade Hand-Sanitizing Panic-Reduction Solution...