Colorvision Spyder Pro 2 comes with an accessory so it can be used for calibrating monitors. I happen to own one, but I'm not really sure how well it works. I guess that you may need a real spectrometer to get it really right. The spyder pro is cheap, so it may be worth a try.
The GretagMacbeth Eye-One with the Beamer module works great. I never travel without it.