measure a spoke on one side of the wheel, and then measure the opposite spoke, on the other side of the wheel, if they are diferent, get the wheel trued, although it is suposed to kinda be like because of the gear things...
do the spoke measuring thing, then get it done at the shop
its nothing to do with spoke measurments. just take tthe bike in to a shop with the wheel in and they will just sort it for you if there any good. i know my shop would