The IE8 beta pages are now up and live. The download is not yet resolving to an application.  updates from this morning; it works now, the application is downloadable, and IE8 doesn’t render as expected.
I didn’t feel this was worth of a new post so I’m updating this one instead. As of this morning the beta is now downloadable. I have installed it on a Virtual Machine and am largely happy with it (the hyperlink hover fade-in now works in IE!). The IE7 switch is a little disappointing as you need to close all instances of IE8 before the engines switch. Better than nothing, but it does make it impossible to have an IE7 and IE8 open at the same time. Other problems include an apparent inability to render generated content properly (as shown on the screen-shot below, note how my thumbnails are all square edges when they ought to be rounded - learn how I made that effect), and IE8 retains the IE6/7 bug of thinking my page is wider than it actually is. This is to do with the placement of the skip-links at the top of the page.