<script language="javascript1.2">
<!-- begin
var no = 25; // количество снежинок
var speed = 10; // скорость падения снежинок
var snowflake = "http://i014.radikal.ru/0712/02/7f9240ea08b1.gif";

var ns4up = (document.layers) ? 1 : 0; // browser sniffer
var ie4up = (document.all) ? 1 : 0;
var dx, xp, yp; // coordinate and position variables
var am, stx, sty; // amplitude and step variables
var i, doc_width = 800, doc_height = 600;
if (ns4up) {
doc_width = self.innerwidth;
doc_height = self.innerheight;
} else if (ie4up) {
doc_width = document.body.clientwidth;
doc_height = document.body.clientheight;
}
dx = new array();
xp = new array();
yp = new array();
am = new array();
stx = new array();
sty = 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
sty[i] = 0.7 + math.random(); // set step variables
if (ns4up) { // set layers
if (i == 0) {
document.write("<layer name=\"dot"+ i +"\" left=\"15\" ");
document.write("top=\"15\" visibility=\"show\"><img src=\"");
document.write(snowflake + "\" border=\"0\"></layer>");
} else {
document.write("<layer name=\"dot"+ i +"\" left=\"15\" ");
document.write("top=\"15\" visibility=\"show\"><img src=\"");
document.write(snowflake + "\" border=\"0\"></layer>");
}
} else if (ie4up) {
if (i == 0) {
document.write("<div id=\"dot"+ i +"\" style=\"position: ");
document.write("absolute; z-index: "+ i +"; visibility: ");
document.write("visible; top: 15px; left: 15px;\"><img src=\"");
document.write(snowflake + "\" border=\"0\"></div>");
} else {
document.write("<div id=\"dot"+ i +"\" style=\"position: ");
document.write("absolute; z-index: "+ i +"; visibility: ");
document.write("visible; top: 15px; left: 15px;\"><img src=\"");
document.write(snowflake + "\" border=\"0\"></div>");
}
}
}
function snowns() { // netscape main animation function
for (i = 0; i < no; ++ i) { // iterate for every dot
yp[i] += sty[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;
sty[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()", speed);
}
function snowie() { // ie main animation function
for (i = 0; i < no; ++ i) { // iterate for every dot
yp[i] += sty[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;
sty[i] = 0.7 + math.random();
doc_width = document.body.clientwidth;
doc_height = document.body.clientheight;
}
dx[i] += stx[i];
document.all["dot"+i].style.pixeltop = yp[i];
document.all["dot"+i].style.pixelleft = xp[i] + am[i]*math.sin(dx[i]);
}
settimeout("snowie()", speed);
}
if (ns4up) {
snowns();
} else if (ie4up) {
snowie();
}
// end -->
</script>

Вместо "адрес_снежинки" - вписать адрес той картинки, которая будет играть роль снежинок.