How can I replace pull switch lights with wireless remote receivers / switches?
Something like the Carlon HW2162 screw-in wireless remote switch can do the job. I used something similar to replace a pull chain in an attic. Now I can turn on the light at the door, and not have to stumble through the dark to the middle of the attic to find the pull cord.  It will set you back about $30. The installation requires no wiring and takes about 5 minutes.