I have read that my shimano 105 front shifter will work with either a triple setup or a double. My bike currently has a triple, but I have bought a double crank, bb, and new front and rear derailleurs. Once I install my new parts how do I set up the front shifter for a double?
Actually you set it up the same as you would for a triple.
Go to http://www.parktool.com for detailed instructions. Do each step in proper sequence leaving nothing out. The Shimano instructions are also available online.