How to take a screenshot with an Android phone?
How to make a simple screenshot with my HTC Desire S with the Android 2.3.5 version?
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My HTC Amaze takes screenshots if I press the power button and the home button at the same time. You should hear a camera shutter sound and the screenshot will be in your Gallery App under "Camera Shots". Many of the HTC phones with the newer version of Sense have this functionality now.
If this doesn't work, there are a lot of apps you can get from the Android Market that allow you to take a screenshot from your phone without rooting it. I've used Shoot Me, Screenshot It and Screenshot UX with good results, although not all of them are free apps.
You can also take screenshots while the phone is attached to your PC or Mac if you have the Android SDK installed (doesn't need to be rooted), but this is a little more involved and you have to have the phone connected to the computer with the USB cable. You don't need Eclipse to do this, just search "DDMS" for some more info, although this is probably way more involved than most people want to get into.