http://www.bhphotovideo.com/c/product/465156-REG/X_Rite_EODIS2_i1Display_2_Colorimeter_Monitor.html

Every lab I've worked in had an X-Rite color meter, so I went ahead and got the X-Rite color calibration hardware. Went middle of the road on price - there's cheaper, and certainly more expensive, but this little puppy ($189 in the US) works like a charm and was easy to use.

I can't see why it wouldn't work for dual-monitors, but then again, I haven't tried - I use single widescreen monitors for my workstations.

I've heard god things about the Spyder 3 as well.

Hope this helps-

-Lew