WinBeta has reported that Microsoft has compiled build 8042 of the upcoming Windows 8. The full string number of this build is 6.2.8042.0.110707-1940 which also implies that the build was compiled on July 7.With the WPC 2011 event underway, we are expecting to see a new build demonstrated by the Microsoft folks or at least an update on the progress. Microsoft has demonstrated some of what we can expect from Windows 8 with a new touch friendly UI and tight cloud integration.
Microsoft has been very tight on the development of Windows 8 even with a few leaks which have found their way to the public. The last version which was leaked was Windows 8 build 7989, so if you see a later version anywhere online stay clear as it wont be a legit Windows build.