How to use PNG background transparancy in IE6

It is known that we can't use PNG transparancy as a background in IE6.
This example below is a hack to do it, by utilising Alpha Image Loader :

#top {
background-image: none;
background-repeat: repeat-x;
float: left;
height: 12px;
width: 502px;
filter: progid: DXImageTransform.Microsoft.AlphaImageLoader(src=images/2.png,sizingMethod='scale');
}