Windows 7 RTM (English) was released to MSDN and Technet Subscribers on August 6th, 2009. If you are an ISV Partner (Independent software vendor) or a IHV (Independent hardware vendor) partners, then you too can download Windows 7 RTM from either Microsoft Connect or MSDN.
For Gold Partners, Action Pack Subscribers, OEM’s, Business Customers, IT Professionals and other Enthusiasts - check this link When will you get Windows 7 RTM? There’s also a nice chart at the bottom of the page that lists out important dates.
If you are a developer and plan to create applications on Windows 7, check this Windows 7 Training Kit For Developers.
The Windows 7 Training Kit for Developers includes presentations, hands-on labs, and demos to help you build Windows 7 compatible applications.
For regular updates on Windows 7, make sure you check the Windows 7 Team Blog