Microsoft has already announced two upgrade special offers for users with machines running Windows 7 and other versions of the OS.

Some Microsoft customers and partners, however, will get early access to Windows 8 this month, including developers, who will be able to download the OS through their MSDN (Microsoft Developer Network) subscriptions starting on Aug. 15. On that same day, IT professionals testing the OS in their companies will gain access to it via their TechNet subscriptions.

On Aug. 16, the gates open for customers with Software Assurance contracts, who will get access to the Windows 8 Enterprise edition, as well as for Partner Network members who will be able to get Windows 8.

Four days later comes the turn for Microsoft Action Pack Providers, and on September 1st Volume License customers without Software Assurance will be able to buy Windows 8 from Volume License Resellers.

With Windows 8 and its new Metro interface optimized for devices whose screens support touch and stylus input, Microsoft will try to improve the operating system's weak position in the tablet market, widely dominated by Apple with its iPad.