$sorgu = mysql_query ( "SELECT * FROM videos" );
while ( $oku = mysql_fetch_assoc ( $sorgu ) ) {
if ( get_headers ( "http://xxx$oku[yt_id].flv<br>\n" ) ) {

echo "dosya var";
}
else {
echo "http://xxx/$oku[yt_id].flv <br>\n";
}
}