Why do your pictures sometimes look like they've been stained yellow or red while others look green or blue? That's all because of your white balance setting. The easiest way to take better pictures is to adjust the white balance and you can follow this chart to tell you how.
Because some lights will give you a different effect, this color temperature scale made by Digital Camera World will tell you where different light sources fall and what setting your camera's white balance needs to be.
To be more specific on the color temperature, Wikipedia categorizes different light sources like this:
1,700 K - Match flame 1,850 K - Candle flame, sunset/sunrise 2,700–3,300 K - Incandescent light bulb 3,000 K - Soft White compact fluorescent light bulb 3,200 K - Studio lamps, photofloods, etc. 3,350 K - Studio "CP" light 4,100–4,150 K - Moonlight, xenon arc lamp 5,000 K - Horizon daylight 5,000 K - Fluorescent light tubes or Cool White/Daylight compact fluorescent light bulb 5,500–6,000 K - Vertical daylight, electronic flash 6,500 K - Daylight, overcast 6,500–9,300 K - LCD or CRT screen