Internet Explorer: Google Chrome Frame, the IE add-in that displays certain web pages with a Chrome-style engine, has updated to beta, adding Chrome 5.0 features like HTML5 video and audio support, while also tightening its integration with Internet Explorer features.
With the HTML5 support, you get to use YouTube's no-Flash-needed version, and try out cutting-edge web apps like Google Wave in a browser that otherwise would choke out. Google has also made Chrome Frame behave better when using IE's inPrivate browsing, clearing the cache and blocking cookies, so privacy-aware users don't have to sacrifice anything to install Chrome Frame.
Chrome Frame is a free download that works inside Internet Explorer, and only activates on sites that are coded to request it. To get more regular and cutting-edge (and, possibly, unstable) updates to Chrome Frame, you can join the dev channel.
Google Chrome Frame - Now in Beta [Chromium Blog]