I want to do this too!
First, there are 2 bulbs in each housing. The amber bulb is a 2357A. A white bulb that fits the same socket would be a 1157. Although if I ever get around to it, I'm going to use an LED bulb for the driving lights. Cut the wires for the driving lights and run them to the ignition.
BUT! If you notice inside the housing there is an open gap between both bulbs. You will have to separate both bulbs or the different lights will mix together and look like ****.
What I planned to do was, cut with a hacksaw a slot on the back of the light. Slide in a thin piece of plastic to separate the lights and glue it in place.