For Firefox users, here is a simple, time saving extension when developing websites or looking at sites that only render well in IE. IE Tab is a new extension that launches IE within a Firefox tab. The extension will put an IE icon on any tab opened in IE and also gives you the ability to add sites to a list of URLs you want to always view in IE. The one quirk I see is that if you put site a site like myweb.com in the ie tab filter list and myweb.com redirects to www.myweb.com the rendering in IE will not carry over when www.myweb.com loads in the tab.
If you want to see the thing work take a look at Mozilla’s home page to see the difference in a tab open in Firefox versus one in IE.