Monitor Calibration Tools and Software
It really depends what you're doing, and how important the colour-accuracy is.
If it's just "so they look the same", you can probably do it by eye. Bring up a photo on both montiors (Macie the KODAK Digital LAD Test Image is good for this), then fiddle with the settings until they look the same. Typically you reset everything on both monitors (which can often get you most of the way there), then adjust the contrast, then brightness then colour-balance till the two match.
I also found "Monitor Color Calibration for free using your DSLR", which describes using a DSLR to calibrate a monitor. It's not exactly a one-click-and-everything-is-perfect setup, but it seems to work..
The Datacolor Spyder series seem to be about the most popular monitor calibration probe, and are quite reasonably priced (about $150USD according to froogle.com)
At the last place I worked, they used (well, originally developed!) cineSpace for monitor-profiling/calibration - although it's not exactly cheap, from here, "Pricing for cineSpace starts at 1,000.00 USD for a basic cineSpace license package". cineSpace is likely overkill for what you are doing, although you do mention your machine having a nVidia Quadro card which implies some form of high-end visual "stuff"..
In short, try doing it by eye (or using a DSLR). If that doesn't work, look into the Spyder 3.
As I'm sure you know, monitor calibration is one of the blackest of the black arts of modern computing. I do a lot of photo retouching and video special FX work and I spend way too much of my time worrying whether what I'm seeing is what I'm getting! My recommendation would be a hardware solution of some kind: software only solutions are really not much better than guesswork combined with trial-and-error. A lot of the studios I work in have four-figure price calibration solutions (and five-figure price monitors!), but for home use, I have a DataColor Spyder 3 Pro which cost me about £110 in the UK. A friend uses a Pantone Huey Pro which I think was about £90. There is also a cheaper Huey. I can personally highly recommend the Spyder: since I got it, my monitors stay beautifully in sync and I spend a LOT less time worrying and fiddling about.
I just matched two Eizo L768 monitors. One is connected via VGA, the other via DVI. As of @bert answer I used the DVI monitor as reference and tried to change the VGA monitors settings to match the DVI monitor.
This was my strategy:
- First I went to http://tft.vanity.dk/monitorTest_scale.html and resized my browser window over both screens.
- I opened a white screen and noticed, that the DVI monitor looked more red. But roughly the same brightness.
- I opened a red screen. No noticeable difference.
- Blue screen: Yes, there was a difference. On the VGA monitor I opened the gain settings of my monitor, which were red 100 %, blue 100 % and green 100 % by default. Lowered blue to 89 %.
- Green screen: Difference! Lowered green in the gain settings to 89 %.
- Now I opened a video from the German news television. The speakers face was still a bit pale on the VGA monitor. So I opened the saturation settings of the monitor and raised them to 15.
- Now some other parts of the picture in the news (the blue background of the studio) was to bright). I opened the brightness settings of the monitor and changed them to 78%.
- Watched the whole news with this setting and the video screen resized to both monitors. Ok.
- White screen again. Ok.
Finished. Might be useful to others.
If it's an LCD monitor you can use www.lagom.nl lcd-test following the instructions carefully.
And Calibrize if you're using MS Windows.