Screen capture is built-into ICS and Jelly Bean.
"Saving DROID Razr's, one battery at a time. :-)" - (credit SallyC)
Avatar is Maxwell Smart, AKA Agent 86, from "Get Smart" (with his signature "Shoe Phone"), a SitCom TV series by Mel Brooks & Buck Henry, based on the spy thriller series, "The Man From U.N.C.L.E.".
"Guidelines of Conduct" for DroidForums.net
Current lineup: Galaxy S5, iPhone 5S, Note 10.1 (2014)
Previous smartphones: Note 3, HTC One, Note 2, Galaxy S3, One X, RAZR MAXX, Galaxy Nexus, Rezound, Note, iPhone 4S, Bionic, Stratosphere, Charge, Vitality, Incredible 2, Thunderbolt, Palm Pixi Plus, Droid 3, Fascinate, Incredible, Droid Pro, Droid 2 Global, Droid X, Droid, Treo Pro, Touch Pro 2, Touch Pro, Q9m, XV6800, XV6900
Previous tablets: iPad Mini, Transformer TF300, Evo View, Transformer Prime, Transformer TF101, Thrive, gTablet
The easiest way on the S3 is to do a palm swipe across the screen " pretty much touching it while you swipe your hand across the screen" to do a screenshot.