preview files in Nautilus ?

[Paul Ionescu <i_p_a_u_l yahoo com>]

Hi all,

I remember some years ago, there was an option that enables preview of a
file while hoovering with the mouse over it. 
And even better, if the file was a sound, then you could hear it in, and
if the file was a movie, you could see a preview of the movie.
In KDE it still exists (with the exception that movies are not previewed)
How can I enable this functionality in Nautilus ?
I would also prefer that the preview should be selectable in the left part
or Nautilus, or like a tool-tip.
I searched this list but I found no answer.

Thanks,