Windows 7 Team blog compiled few FAQs regarding availability of Windows 7. That will help you to get Windows 7, once it complete.

Q. How do I get Windows 7 RTM?

A. The answer depends on who you are:

• MSDN & TechNet Subscribers: Subscribers will be able to download the final version of Windows 7 a few weeks after announce RTM.
• Volume License (VL) Customers: Customers with Software Assurance for Windows will be able to download the final version of Windows 7 Enterprise a few weeks after we announce RTM. Customers without Software Assurance will be able to purchase Windows 7 through Volume Licensing on September 1st.
• Consumers, Enthusiasts, & Beta Testers (Everyone else): The retail version of Windows 7 will be available in stores October 22nd. If you pre-ordered Windows 7, it should be delivered sometime around the October 22nd timeframe (depends on the retailer). You can pre-order Windows 7 today through many online retailers like the Microsoft Store.
• On New PCs: OEMs are expected to start shipping new PCs with Windows 7 pre-installed on them around October 22nd.

Q. Can I continue to use the Windows 7 Release Candidate (RC) until I receive the RTM version?

A. Yes, you can continue to use the RC until it expires on June 1st, 2010 (expiration starts March 1, 2010 – this is when the reboots start – final expiration on June 1). Please note that “in-place” (or direct) upgrades from the Windows 7 RC to RTM will not be supported. You will be required to do a Custom installation (aka “clean install”).

Q. I am a TechNet or MSDN subscriber. Will I get a product key?

A. MSDN and TechNet subscribers, as well as Volume License customers will have access to product keys (PIDs) when Windows 7 is made available to them. Product keys for Windows 7 RTM will be different than the product keys used for Windows 7 Beta and the release candidate. Windows 7 Beta or RC product keys *will not* work with Windows 7 RTM.

Q. I am using one of the so-called “leaked” builds of Windows 7, how will I know if it is the real deal?

A. As always, beware of what you download. There are many bogus copies of Windows 7 floating around the Internet. More often than not, they contain a rather nice malware payload. And don’t believe everything you read on the Internet. When Windows 7 hits RTM, it will be announced here. Until that happens, any builds you are likely to see on the web are either not the final bits or are laced with malicious code.

Q. How do I get a 64-bit copy of Windows 7?

A. The Upgrade and Full packaged retail product of Windows 7 Home Premium, Windows 7 Professional, and Windows 7 Ultimate will come with both 32-bit and 64-bit DVDs. With Windows Vista, the 64-bit version was only available with Windows Vista Ultimate. Due to the incredible adoption of 64-bit today and customer feedback, we decided to change this for Windows 7. Now all copies of Windows 7 in developed markets will ship with both 32-bit and 64-bit DVDs.

Source: Windows 7 Team Blog