Microsoft just announced a beta version of Internet Explorer 8 is available.
I didn't try it yet - the link they've supplied for beta registration (http://connect.microsoft.com/InvitationUse.aspx?ProgramID=2038) points to a page that does not exist. Probably will be up in a couple of days.
As always, I would recommend not installing any (beta) version of IE on your main machine. But that's what VMs are for. Use the beta to test whether your site or application can withstand the new version of IE without breaking. I'm just glad they didn't make it a "Vista only" browser.
Read more here.
Seems like someone jumped the gun and published an internal Microsoft memo, inviting someone to a private beta. That's why the link doesn't work. However, the memo does discuss a public beta soon. So I guess "patience" is the keyword here .
It's now official: you can download the beta from the MS download site, in one of 4 flavors:
XP version, 2003 SP2 version, Vista and 2008 Server version, and Vista/2008 Server 64 bit version.