Making IE8 Emulate IE7
As you probably know, Microsoft Internet Explorer 8 was "officially" released yesterday. If you were caught off guard by this and haven't had time to test your sites in IE8, don't lose sleep; you can make IE8 render pages like IE7 using a simple META tag.
<meta http-equiv="X-UA-Compatible" content="IE=EmulateIE7" />
It doesn't get much easier than that. Don't use this functionality as a crutch for too long though!