Now Available: IE 10 Platform Preview 4

Microsoft released the fourth version of its Internet Explorer 10 platform preview. It follows closely behind platform preview 3, which was bundled up with the debut of the Windows 8 developer preview that appeared at the Microsoft Build conference in mid-September . Microsoft's platform preview releases seem to occur whenever the development team is seeking feedback on browser features, rather than according to a fixed schedule.

http://mcpmag.com/articles/2011/11/29/ie-10-platform-preview-4-out-now.aspx