You can read more about the Windows Server 2008 R2 RTM on the Windows Server Team blog, while Microsoft blogger Brandon LeBlanc broke the Windows 7 news earlier this afternoon on the Windows 7 team blog.
Here's an excerpt:
I am pleased to announce that Windows 7 has RTM’d!
As I mentioned previously, RTM officially happens only after sign-off occurs. What happens is a build gets designated as a RTM contender after going through significant testing and meeting our quality bar for RTM. Then, it goes though all the validation checks required for RTM including having all languages of that build completed. If all the validation checks have passed – sign-off for RTM can occur. Today after all the validation checks were met, we signed off and declared build 7600 as RTM.
Windows 7 is scheduled to be available at retail on October 22, 2009. An exact general availability (GA) date for Windows Server 2008 R2 has yet to be announced, but it is widely expected to be available about the same time as Windows 7.
Update: A Microsoft spokesperson provided us with some additional details regarding the availability of Windows Server 2008 R2, and I've added a Microsoft-produced video from YouTube--sourced from the Windows 7 team blog--that provides a humorous look at the Windows 7 RTM sign-off process (both below):
Windows 7 will be generally available on October 22nd, with Windows Server 2008 R2 available on or before that date. However, existing Volume Licensing customers will be able to download Windows 7 on August 7th and Windows Server 2008 R2 in the second half of August.