An update to Internet Explorer 9 Beta is available from Microsoft as of yesterday (November 23rd 2010).
This is an update to the full browser as opposed to the developer preview build which isn’t the full Internet Explore, although the preview build does work side-by-side with any other version of IE.
Not much is mentioned about what the update brings. Rumours circulate that a beta 2 would see the day before release candidates. Stay tuned.