I use two different applications depending on my needs.
'Clipboard Monitor' which was made available by one of the members here a while back or 'Snapper' which has the ability to grab screens from the main, secondary or both monitors and can also add location info (lat., long., near to, etc.) to the screenshot which is pulled directly from your location in FS9 or FSX.
Don't forget that FSX comes with it's own in-built screenshot feature too. Just hit the 'V' key and images will be saved in .BMP format to your 'C:\Users\'Yourname'\Pictures\Flight Simulator X Files' folder. I tend to use that feature when I want high quality screenshots as the images are much better than Snapper or CBM as I have those set to capture in .JPG format. One thing I have found when using the in-built FSX screenshot grabber is that the images all need to be run through Photoshop (or similar) to have a slight sharpening effect applied as they appear to be slightly out of focus with soft edges by default.
Last edited by Tako_Kichi on 11 Apr 2012, 17:40, edited 1 time in total.
Snapper is great, though I have to say that since going from 32 bit Vista to 64 bit W7, I have had it crash a few times. No biggy as a restart of Snapper seems to work. I think it just gets bored sitting in the taskbar unused for long periods of time.