Its probably referring to Organic LED's as opposed to old style LED's. OLED is really brand new technology, the first OLED television was made by Sony last year, was 10 inches and cost a fortune, the equivalent of a 40" 1080p plasma. Ive seen laptops with OLED displays, like the Macbook air, and yes it saves battery and has a much more vibrant rich display then normal LCD TFT displays.
well....... I am not sure what you are talking about specifically, the are two things it could be
1) OLED display, a display comprising entirely of millions of tiny LEDs
2) LED backlit LCD, this is a normal LCD, but instead of a florescent backlight, it has hundreds of LEDs, this saves power, and allows the backlight to be dimmed locally to get "blacker blacks"