Mouseover zoom effect

Lots of people have asked this, but so far no answer that works for me.

How do I get an image in ng gallery to produce a jump out zoom effect like a moveable lens on mouseover?

Ideally a free plugin/extension would be great, or maybe just some code with clear insructions on how to make it work?

Any help much appreciated,

Robin.

http://wordpress.org/extend/plugins/nextgen-gallery/