Scrolling monitor

Scrolling monitor

Ran across an interesting effect today on a news website. While scrolling down, once the page reached a certain point, a pop-in slid in from the bottom right of the window showing a related news story. If you scrolled up again, the pop-in slid back out (used a negative right position).

I'm looking for a JQuery plugin or other script that will let me monitor the position of the page while scrolling. Anyone have any ideas?