It's definitely different for everywhere that you get photos printed. Their printers may not be calibrated the same as your monitor, or you might be using a different colour setting that produces different colours (e.g. sRGB v CMYK). You might try a local lab that prints digitals and see how the pictures turn out because that way if they turn out dark or whatever it's easier to go back to them and see why and what you can do on your end to fix it so you get better prints
Hope that helps.