The thread about the conference last summer (HERE) contains the reason for the effects in those videos.
(In fact the conference was largely about cellphone towers rather than the handsets themselves, and one of the scientists made the comment that since we do hold handsets close to our face, effects from them are going to be somewhat greater than from the towers, which are going to be at least several feet away).
So how is it that cellphone radiation can pop popcorn? Because it heats things up. The effect is purely thermal. The radiation is incapable of breaking chemical bonds; this is not a matter of debate, it’s a matter of the wavelength of electromagnetic radiation that the phones emit—which is longer than visible light, hence at lower energy. If you’re worried about cellphone radiation, you should be very worried about allowing sunlight to touch your skin. Sunlight contains ultraviolet rays which can break chemical bonds and hence cause skin cancer. It can also pop popcorn if you do the same sort of trick that these folks did with their handsets: just use a magnifying glass or a few mirrors to focus the radiation.
Any link between the disappearance of bees (most likely due to a virus or some pesticide stress) and cellphones is completely speculative. Bees don’t use cellphones and typically aren’t anywhere near either handsets or towers. If they were affected by them they would be killed off by radio and TV emissions that have been going on for decades, not to mention the sun that I already mentioned.