Taking screen shot in a mobile is so easy. Just hold the home and power button together for a second. This will grab the current screen as image in photo gallery.
Tested in HTC Explorer and iPhone 3GS. Yes, this tip is applicable for both Android and iPhone. Applicable for any iOS device and latest versions of Android. I do not know who copied from whom ;-)
Step 1: Run the android app in AVD.
Step 2: Go to Eclipse menu -> Window -> Show View -> Other -> Android -> Devices
This is a difficult way, but still an option.
If you have got some other option, let us know.
This Android tutorial was added on 14/09/2012.