I bought about the same thing from another website. If you want to measure CPU temp, i would recommend putting it on the back of the motherboard, where the cpu is. Make sure you realize though, wherever you put it, it wont be 100% accurate.
For mounting, i bought some heavy duty 3m double sided mounting tape, and mounted it to the inside of the case, so i can look through the window.
Look at the thermometers on frozencpu.com, they offer a cabling service where they cover the cable and heatshrink it in whatever colors you want.