How do I do layers in IE - there's no <layer> tag?
Layers in the sense of the Document Object Model can be applied in both browsers. <layer> the markup tag is only supported in Netscape 4 and should not be used for crossbrowser purposes. To create layers you can use DOM supported tags like <div> and <span>.
A.MacNair's DHTML tutorial is a good start to help you understand the basics of Dynamic HTML. It is not finished, but it will introduce you to layers.
<div id="blockDiv0" style="position:absolute; left:4px; top:4px; z-index:4"> the stuff you want in a layer </div>