'Still of the Night' is by Whitesnake and the singer had a band with Jimmy Page for awhile called Coverdale/Page. He's been touted as being a R. Plant wanna-be but is an awesome vocalist.
I believe the part you're talking about is the breakdown in the song where it sounds like violins playing. He's just picking in that part but it's similar to the Ebow effect.
Here's a video of it live by the original guitarist, John Sykes, who wrote and recorded the song. One of my favorite guitar players (he's singing it too):

http://www.youtube.com/watch?v=cWn_p0jxGMs

Check it out at about 5mins.

The Whitesnake singer, David Coverdale (originally in Deep Purple) fired the whole band after their most successful album from 1987 which was largely in part due to John Sykes writing skills. None of the musicians in the MTV 'Still of the Night' video actually played on the album.

Here's the band that did :
Neil Murry on bass (Rainbow, Black Sabbath, Ozzy), Ansley Dunbar on drums (J. Starship, S. Hagar, D. Bowie, UFO, Zappa, Jeff Beck) and Don Airey on keyboards (Rainbow, Black Sabbath, Ozzy, Judas Priest, Gary Moore, Thin Lizzy).
I guess they weren't good enough for Coverdale ;) Whitesnake never reached the success it had with the lineup on 'Still of the Night'.
Oops! -egos, they'll do it ever time.

It's funny that you said "heat of the night by led zepplin" because I google'd it and there's a Zep bootleg by that name.