Image stabilization (IS) is a family of techniques used to reduce blurring associated with the motion of a camera during exposure. -- Wikipedia

Aka: When taking a photo, Image stabilizer helps reduce camera shake - hence making the photo blur less... or blur none... I don't know the best way to explain.

This post was edited by Chantal7 on Jun 21 2011 12:59pm

thanks

Or you can say that it stabilize your image

I know in DSLRs, the lens shift a tiny bit to counteract handshake thus allowing slower exposures. It's overrated in my opinion though, there's only a few cases where it comes in handy.