Horizontal scroll image slideshow is a WordPress plugin by Gopi.R that will create the Horizontal scroll image slideshow gallery in sidebar widget.
Horizontal scroll image slideshow lets you showcase images in a horizontal scroll like fashion, one image at a time and in a continuous manner, with no breaks between the first and last image.
Demo: http://www.gopiplus.com/work/2010/07/18/horizontal-scroll-image-slideshow/
Download: http://wordpress.org/extend/plugins/horizontal-scroll-image-slideshow/