WP Plugin to emulate the “Next Post” buttons you see once you scroll to the bottom.

Just like the NYTimes button, upPrev allows WordPress site admins to provide the same functionality for their readers. When a reader scrolls to the bottom of a single post, a button animates in the page?s bottom right corner, allowing the reader to select the next available post in the single post?s category (the category is also clickable to access an archive page). If no next post exists, no button is displayed.

Video: http://www.youtube.com/watch?v=ZTrQGhWhCKs

Plugin: http://wordpress.org/extend/plugins/upprev-nytimes-style-next-post-jquery-animated-fly-in-button/