I recently have started using an awesome little JavaScript code to help me get over the time wasted developing my CSS and making it compliant with IE6. The code takes the HTML and CSS and makes IE6 display it as IE7 would display it. They also have some in the works for IE8 as soon as it comes out. This code helps to allow you to only develop for one version of Internet Explorer. It has been a life saver. I haven't run into any problems yet. So far so good.