Automatically append the next page of posts (via AJAX) to your page when a user scrolls to the bottom.
Infinite scroll extended to single post pages
Infinite scroll for your site with “paginator” and an easy way to go to the top/botttom.
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.