Mary Jo Foley has contacts with sources who have been correct with Windows in the past and Microsoft are planned to release a Technical Preview either at the end of September/Early October.
Microsoft is aiming to deliver a "technology preview" of its Windows "Threshold" operating system by late September or early October, according to multiple sources of mine who asked not to be named.
She wasn't too sure when first writing her blog that the Tech preview will be public or not. Later on she says:
Update: One of my contacts who has provided accurate information on Windows in the past said the Threshold tech preview will be public and available to all those interested.
Windows 9 is to include a mini start menu and to allow Modern UI applications in window mode for desktop users. Let's see if Mary Joe Foley's sources are correct. You can read her blog here:
http://www.zdnet.com/microsoft-to-deliver-windows-threshold-tech-preview-around-late-september-7000032668/