The best way to calibrate your monitor(s) for photography is to use a hardware calibration device. These devices are known as Colorimeters.
Below is a list of the calibration devices available with links to their manufacturers websites
(if a member knows of any others, please feel free to add them to this thread)
Munki : http://www.colormunki.com/
Eizo : http://www.eizo.com/global/products/...PIX/index.html
LaCie : http://www.lacie.com/products/product.htm?id=10154
Pantone : http://www.pantone.com/pages/product...t.aspx?pid=562