Calibrating external monitors (HDMI, Mini DisplayPort)
Solution 1:
You have a couple of options, none of which are built into Windows, but will get the job done:
1)I'd recommend this for something where you want the color close on both screens. One of these tools, and then tweak your color settings on both monitors until they are how you want them.
2)Professional shops like paint shops and printers use extra hardware to get the color just right on EVERYONE's machine, something like this. You basically hook it up and let it do it's thing.
So you have options, just depends on how serious you want to get.