The single largest complaint about Android is that there's no way to take screenshots in the Android OS without rooting it. We've received word that all this will change in ICS (this feature also exists in HoneyComb we believe) - you will be able to take screenshots directly from ICS natively without rooting.
Google has finally made this happen and to take a screenshot, all you have to do is press and hold down the volume down and power button simultaneously and the screenshot will be taken instantaneously and saved into the gallery. That's it! Its that simple. Some of the phones already have this feature built in such as the Galaxy S II and some HTC phones with Sense 3.0 in it but these are enabled by the manufacturers and does not come out of the box.