I also just got a DS18B20 and am mostly happy. The wires were red,yellow, green. I eventually figured out that:
red: 5v/3.3v
yellow: gnd (what?!?!)
green: data
I know that there is no universal color scheme for these kinds of things, but this one was just crazy. Seriously, yellow for ground? In this case due to my setup I was able to try different combinations without risk of frying anything, but I can imagine some contexts where trial and error isn’t an option. Please try to include color code info when you ship components.
Otherwise, once I got everything sorted out I stuck the thing under my tongue and got 36C. Awesome!