The CRM 2011 Implementation Guide was released last week, and it looks like the CRM 2011 SDK has also been released. As far as I can tell, the SDK is a live (as opposed to beta) release, though the hands-on labs were built on beta code. The SDK documentation has version 5.0.1, and it includes binaries with version 5.0.9688.583 which are claimed to match those for CRM 2011 Online. We'll see what version number we get with the RTM code.
And the CRM 2011 Developer Training Kit has also been released recently.
I'm deliberately using the term released to indicate that they are publicly available (as opposed to 'launch', which I consider a marketing event).