Don't know that it really makes a difference in connecting or using with the Arduino, though it surely makes a difference to somebody.
I purchased a DS18S20 off EBay so, naturally, there is no documentation. The actual sensor is encapsulated in a metal tube with a shielded 2-wire cable attached. At the other end is a three-wire plug. In the plug it has the shield, white wire, then red wire, in that order. I think it would be safe to assume the shield is the ground, but does not answer the bigger question as to which is the data line and which is the power.
If we match the sequence on the data sheet, we get that the middle pin (white) is the data and the third pin (red) is the power. Am I going to hurt anything if I try this?