AutoPager automatically loads next pages when you reach the end of a page. It works on a ton of sites,Google,Yahoo..
It works well with most other add-ons adblock plus, WOT and most of the greasemonkey scripts.
You can also try AutoPagerLite.
Browse faster—Preview links and images without leaving your current page or tab. Just mouseover any link and a preview window appears to display the content.
Jump-to-word buttons and highlighting for the search box content