Microsoft has released two new updates for Internet Explorer 8 on Windows 7 RC, via Windows Update. The first update applies only to Windows 7 RC, and will be fixed in the Windows 7 RTM. The first issue resolved is one which, according to the Microsoft Support site, caused the browser to hang, and show this error message: "A webpage is not responding on the following website: (Website name)".
The update for this issue requires the browser to restart before it can be applied. The issue is apparently caused by a timer used to detect when web pages have stopped responding, which is normally fine. However, on lower performance computers, or on computers under high load conditions, this can sometimes cause IE8 to think that the website has stopped responding, when in fact it is just loading slowly.
The second update is an update for the Compatibility view list, which, in Microsoft's very own words "makes Web sites that are designed for older browsers look better in Internet Explorer 8. When you install Internet Explorer 8, you can decide whether the sites that you visit should be displayed in Compatibility View". Users may or may not have to restart their browser for this update.
The updates are delivered by Windows Update, so performing an update search should install them, if they aren't installed automatically.