Please identify a song using only four pieces of info...

1) The chorus is a guy singing in falsetto "It's youoooooooooooooooo,
it's youoooooooooooooo, it's youooooooo."

2) The song is very ambient and contemplative, but with a so-called
"alternative" feel.

3) The group appeared on HBO Reverb about a year ago and played that
song.

4) The song was used in the "Slaves of Las Vegas" episode of CSI.

Hello.

The song is "Svefn-g-Englar." The group is Sigur Ross.  The CD is
Agaetis Byujun.
source: 
Elsye's CSI site: CSI Music, hosted by aol.com 
http://members.aol.com/JRD203/csi-music.htm

The song is actually in Icelandic.  And the lyric really isn't "It's
you."  It just sounds like that.

See this newsgroup message archived by Google Groups:

" WHAT was the name of that first song that went on for about
> 20mins, which consisted entirely of the guy singing "It's you" while
bowing
> his guitar.
... it may have sounded like "it's you" but he sings in
Icelandic"
source: Google Groups
http://groups.google.com/groups?hl=en&lr=&ie=UTF-8&selm=3B48DFFC.342217BD%40ntlworld.com



'. The opening track alone, the ten minute "Svefn-G-Englar"
("Sleeptalkers," or "Sleepwalkers"...) ...
a lyric that sounds like "It's you-ouuuu" but in reality translates to
nothing but a lovely sound. "
source: Album review cached by Google:
http://216.239.37.100/search?q=cache:MbmmxGfRUXUJ:www.artandlies.com/analog_roam/archives/000145.html+Svefn-G-Englar+-+Sigur+Ros+%22it%27s+you%22&hl=en&ie=UTF-8&client=googlet

'Svefn-G-Englar," Ágćtis Byrjun's first and only single — until well
past the midpoint of the show. The closest thing to a ballad Sigur Rós
has, it comes with a chorus that sounds as though Birgisson is
repeating "It's you," though in actuality, it's just another one of
his made-up lyrical tricks (most of Sigur Rós' songs are in a
fictional language devised by the frontman).
The true showstopper of the night was halfway through
"Svefn-G-Englar," when Birgisson pulled his guitar to his face and
began to bellow into the instrument's body. All at once, it was as if
his "It's you" was coming from somewhere far-off.'
source: MTV
http://www.mtv.com/news/articles/1443506/20010509/story.jhtml

The Agaetis Byrjun album that contains the song is available from
Amazon:
http://www.amazon.com/exec/obidos/tg/detail/-/B00005IC2H/

The song is also on the Vanilla Sky soundtrack, available from Tower
Records:
http://www.towerrecords.com/product.aspx?pfid=2600474&cc=USD

search strategy: 
csi, music, songs

I hope this helps.

Doesn't get better than this.  Fast and perfect.

Thank you for the tip.
-juggler