Jeffrey Snover of the Windows Server team has announced that Windows Server 2012 is RTM! He has made this announcement yesterday on the Windows Server Blog.
Windows Server 2012 will be general available on September the 4th. Microsoft will celebrate this milestone with an online launch event. Take a look at http://www.microsoft.com/en-us/server-cloud/new.aspx for more details.
For Windows 8 Microsoft announced that this version will be general available on October 26th. However for those lucky people who have a MSDN subscription they can get the bits on the 15th of August. For more details you can take a look at The Windows Blog.
Keep in mind that Hyper-V Server 2012 is not RTM yet.