screens....

[fallia]

i lave a laptop and two additional big screens set up together....i've been using lightroom on one of the big screens....over the weekend i set up the other screen (to use both of the big screens with lightroom)...looking at them with the screensaver on one looks more blue than the other....whats the best thing to do to calibrate them, i've been just winging it with the screen i have and getting things printed (adorama) i haven't been surprised yet but i am bothered by the difference in the two screens

put another way (as apposed to the screens relationship to one another) how do you know that what you see on the screen is what you get regarding color?