iSOblog

…or you theoretically have to pay royalities to microsoft. it’s hard to believe, but they managed to get a patent for

A method and system in a document viewer for scrolling a substantially exact increment in a document, such as one page, regardless of whether the zoom is such that some, all or one page is currently being viewed.

more about it is available here: http://www.itwire.com/content/view/20193/53/