This plugin use the jQuery plugin jCycle. Thank’s to jCycle Easy Gallery is able to override the default standard wordpress gallery and create a gallery with effects.
This will be very easy to do, you need only install and activate this plugin and create and put gallery into your posts, pages or custom posts in the same way you did use untill now.
Added a default CSS style
Added next and previous arrows, add thumbnails previews
First version, it works fine but more features needed