Dual monitor calibration

On my graphics editing computer I have a dual 19 inch LCD monitors. One is a Neovo F-419 and the other is a BenQ FP91G+...

The colours on the Neovo seem much more vibrant and darker, while the BenQ are lighter and less colourful.... How can I tell which one is closer to the the truth when I'm editing photos I've shot with my digital cameras? I use Paint Shop Pro ver 9 and Artweaver for most of my photo editing...

And how can I have photos appear the same regardless of monitor?

Thanks muchly...

Kenmo