Good question!
The accelerating charges in the two examples you suggest are kind of sneaky.
For the light bulb, the electrons of the DC current bump into atoms and shake them around. This creates heat and electrically, we measure resistance. The acclerating charges are the jiggling atoms. The radiation is also known as "blackbody radiation". The sun is another good example of black body radiation.
For the LED, it is a little different. Electrons at one energy level fall down to a lower energy level at the PN junction. The tumble from one energy level to a lower energy level is the acceleration, and it results in radiation. Solid state experts (of which I am most definately not) can provide more precise details.