You can buy a permethrin spray at EMS or REI. Or, if you're paranoid and/or wealthy, you can buy a line of pre-impregnated clothing from LL Bean. The brand is Ex Officio and the line of clothes is Insect Shield. You can buy everything from shirts and pants to socks and hats. The treatment supposedly holds up for 70 Washings.
Never thought I'd buy brand-new clothing from LL to work in the woods, but after a mild case of Lyme a couple of years back, I now fall in the paranoid category.
Of course, in a few years, they'll probably decide that this stuff causes cancer
