este script hace el efecto de caer copos de nieve, pero la imagen del copo no sale, eso si el texto se ve....... auda please!!!
<script language="JavaScript">
var snowsrc="/imagenes/snow.gif"
var no = 10;
var ns4up = (document.layers) ? 1 : 0; // browser sniffer
var ie4up = (document.all) ? 1 : 0;
var ns6up = (document.getElementById&&!document.all) ? 1 : 0;
var dx, xp, yp; // coordinate and position variables
var am, stx, styNav; // amplitude and step variables
var i, doc_width = 800, doc_height = 600;
if (ns4up||ns6up) {
doc_width = self.innerWidth;
doc_height = self.innerHeight;
} else if (ie4up) {
doc_width = document.body.clientWidth;
doc_height = document.body.clientHeight;
}
saltar = new Array();
for (i = 0; i < no; ++ i) {
saltar[i]=true;
}
mensaje = new Array();
mensaje[0]="F E L I Z N A V I D A D";
mensaje[1]="1 AÑO MAS EN INTERNET CON VOSOTR@S";
mensaje[2]="¡¡FELICES FIESTAS!!";
mensaje[3]="FELIZ NAVIDAD OS DESEA PEREZTROFF";
mensaje[4]="";
mensaje[5]="F e l i z N a v i d a d";
mensaje[6]="FELIZ NAVIDAD";
mensaje[7]="";
mensaje[8]="F e l i z N a v i d a d";
mensaje[9]="";
dx = new Array();
xp = new Array();
yp = new Array();
am = new Array();
stx = new Array();
styNav = new Array();
for (i = 0; i < no; ++ i) {
dx[i] = 0; // set coordinate variables
xp[i] = Math.random()*(doc_width-50); // set position variables
yp[i] = Math.random()*doc_height;
am[i] = Math.random()*20; // set amplitude variables
stx[i] = 0.02 + Math.random()/10; // set step variables
styNav[i] = 0.7 + Math.random(); // set step variables
if (ns4up) { // set layers
if (i == 0) {
document.write("<layer name=\"dot"+ i +"\" left=\"15\" top=\"15\" visibility=\"show\"><img src='"+snowsrc+"' border=\"0\" alt=\""+mensaje[i]+"\" onmouseover=javascript:saltar["+i+"]=false; onmouseout=javascript:saltar["+i+"]=true;></layer>");
} else {
document.write("<layer name=\"dot"+ i +"\" left=\"15\" top=\"15\" visibility=\"show\"><img src='"+snowsrc+"' border=\"0\" alt=\""+mensaje[i]+"\" onmouseover=javascript:saltar["+i+"]=false; onmouseout=javascript:saltar["+i+"]=true;></layer>");
}
} else if (ie4up||ns6up) {
if (i == 0) {
document.write("<div id=\"dot"+ i +"\" style=\"POSITION: absolute; Z-INDEX: "+ i +"; VISIBILITY: visible; TOP: 15px; LEFT: 15px;\"><img src='"+snowsrc+"' border=\"0\" alt=\""+mensaje[i]+"\" onmouseover=javascript:saltar["+i+"]=false; onmouseout=javascript:saltar["+i+"]=true;></div>");
} else {
document.write("<div id=\"dot"+ i +"\" style=\"POSITION: absolute; Z-INDEX: "+ i +"; VISIBILITY: visible; TOP: 15px; LEFT: 15px;\"><img src='"+snowsrc+"' border=\"0\" alt=\""+mensaje[i]+"\" onmouseover=javascript:saltar["+i+"]=false; onmouseout=javascript:saltar["+i+"]=true;></div>");
}
}
}
function snowNS() { // Netscape main animation function
for (i = 0; i < no; ++ i) { // iterate for every dot
if (saltar[i])
{
yp[i] += styNav[i];
if (yp[i] > doc_height-50) {
xp[i] = Math.random()*(doc_width-am[i]-30);
yp[i] = 0;
stx[i] = 0.02 + Math.random()/10;
styNav[i] = 0.7 + Math.random();
doc_width = self.innerWidth;
doc_height = self.innerHeight;
}
dx[i] += stx[i];
document.layers["dot"+i].top = yp[i];
document.layers["dot"+i].left = xp[i] + am[i]*Math.sin(dx[i]);
}
}
setTimeout("snowNS()", 75);
}
function snowIE_NS6() { // IE and NS6 main animation function
for (i = 0; i < no; ++ i) { // iterate for every dot
if (saltar[i])
{
yp[i] += styNav[i];
if (yp[i] > doc_height-50) {
xp[i] = Math.random()*(doc_width-am[i]-30);
yp[i] = 0;
stx[i] = 0.02 + Math.random()/10;
styNav[i] = 0.7 + Math.random();
doc_width = ns6up?window.innerWidth : document.body.clientWidth;
doc_height = ns6up?window.innerHeight : document.body.clientHeight;
}
dx[i] += stx[i];
if (ie4up){
document.all["dot"+i].style.pixelTop = yp[i];
document.all["dot"+i].style.pixelLeft = xp[i] + am[i]*Math.sin(dx[i]);
}
else if (ns6up){
document.getElementById("dot"+i).style.top=yp[i];
document.getElementById("dot"+i).style.left=xp[i] + am[i]*Math.sin(dx[i]);
}
}
}
setTimeout("snowIE_NS6()", 75);
}
if (ns4up) {
snowNS();
} else if (ie4up||ns6up) {
snowIE_NS6();
}
</script>
) es: 
jejeje
