The Sinewave Indicator was created by John Ehlers (Rocket Science For Traders pgs 97-99) and this is a few indicators in one. Simply put it is a leading indicator which you don't see too many of those these days. If the blue line crosses over the red line then within the next few bars the price will start an uptrend and if the blue line crosses below the red line then in the next few bars it will start a downtrend. I have also included an immediate buy and sell signal on the 0 line which is green when you should buy and red when you should sell.
Let me know if you would like to see any other scripts or if you want something custom done!