Simply auto loads the previous post as you scroll down the page. Also changes the URL address and the page title from that post.
Infinite scroll extended to single post pages
EasyScroll adds an endless feed of posts to your site wherever you choose (even custom post types!).
With FlickrFlow you can create pages with an infinite stream of Flickr photos.
Automatically append the next page of posts (via AJAX) to your page when a user scrolls to the bottom.
Infinite scroll for your site with “paginator” and an easy way to go to the top/botttom.