IE8 has been released several weeks ago at the MIX Web conference. Next week the actual rollout via Windows Update will start.
I have tested IE8 RTM the past few weeks and can really recommend upgrading. IE8 is faster and more secure than IE7 and has cool features such as tab coloring, standards-compliant CSS 2.1 support and a great built-in script debugger.
If you have not done already, please also update Quero to the newest version, which I optimized for IE8.