A humming noise from a light fixture--when turned on-means what?
No dimmer
Non-fluoresecent

Just a question :D

What type of light are you using, incandescent, neon, CPF.

Is your child's room on the other side of the wall and has he/she left the headphones against the wall with the IPOD on low so as not to disturb anyone? :)

Incandescent!

Washington,

Change the bulb and see if it goes away.