Netflix roll-overs with movie details... how?

What’s the underlying code that Netflix uses to pull off automatically spawning a movie details pop-up when users mouse over a movie poster on their site?

I am putting together a site-wide help system on my website and I’d like to be able to insert ‘help’ icons such as where needed, which when hovered over would spawn a similar netflix-style movie details window with relevant help information. NOTE: Just as Netflix has figured out a way to do in their movie-details window, I’d very much like to be able to include clickable links in the pop-up window

Any suggestions or links to where I can learn more would be sincerely appreciated! Thanks!

Are you more interested in just being able to do it, or learning how to do it?

To clarify: Would you like links to plugins/scripts or tutorials?

I am interested in learning how to do it, and any links to plugins/scripts or tutorials would be greatly appreciated!