Sidebar sliding as in example.

Sidebar sliding as in example.

Hi.
I'm searching for a plugin, or part of code, that allows to do the sidebar sliding effect as on example (when the page is scrolled, right sidebar stays on same position, but when footer or header is reached, it stopes moving):

http://www.rockettheme.com/extensions-joomla/roknavmenu

There is mootools used, but I would like to use jquery.

Would be very greatful for a help.