This BoingBoing article links to a Nature article about a 1mm sheet of plastic that can transmit power to nearby electrical devices. The plastic sheet has organic transistors embedded into the material that control the flow of electricity and copper coils which will actually conduct the power. The plastic sheet can deliver power to devices within a 2.5 cm range to devices with the proper receiving coil. The sheet is currently used to power LED's and (presumably) items with a similar load. According to the Nature article, the sheet is constructed in 4 layers. The layers of the electricity transmitting sheet are printed using screen printing techniques and electronic ink-jet inks.