One of the best things I have in my backpacking 1st aid kit.
Sting-Eze
Of course there's also the old school method...tobacco. Several years ago Boo stepped on a honeybee in the yard while barefoot. I got a phone call at work from my wife telling me how well the Tobacco from one of my cigars worked. When I asked her which humidor she got the cigar from, I already had a feeling. Apparently Monte #4's are awesome at drawing out the "poison" from stings.