Can I screenshot my HTC Legend without rooting it?
This functionality is available with the developer toolkit.  The post is a bit old so newer versions of Android will have different icons and slightly different menus, but it walks you through getting the tools installed and then being able to capture screen-shots.  Also the tutorial is for Windows, but it should work with any OS that you get the Android dev tools running on (Windows, Mac OS X, and Linux).

How to take screenshots of your Android based phone from Windows