Canon makes several series of non-SLR digital cameras; each line of cameras begins with a letter-number designation. The A series is the entry-level tier; they're the least expensive but they also lag in features. The Sx00 Elph series is the most compact. The SX series is mid-tier—larger and more powerful. The G series is the top: it has a lot of the EOS features but lacks interchangable lenses.
Given to me by a friend who retired her old cameras. This is, I believe, Canon's third offering in the compact digital field—an updating of their A5 Zoom from the year prior. The main difference is the slightly better sensor resolution.
For more information: Canon Camera Museum
Camera manual: Orphan Cameras.com
Steve's Digicams has a nice review of this camera.