All web developers run into the issue regarding internet explorer: There are three version that are used extensively (IE6, IE7, and IE8) and they all render pages completely differently. So when you're developing, you need to check your pages on all three versions of IE that are in common usage.

Of course Windows only lets you have one version of IE on your computer at any one time, so this makes things a lot harder. There are solutions like virtual machines and web sites that will render pages in multiple version, but these all significantly slow down development.

But there is a solution that let's you do this exactly the way you want to do it, it's called Internet Explorer Connections (http://finalbuilds.edskes.net/iecollection.htm). And it lets you run all of the versions of IE on your computer AT THE SAME TIME! So you can have windows open in IE6, IE7, and IE8 all open at the same time without having to mess with external sites or virtual machines. This is a huge time saver when you are doing web development and you need to support IE.