The Windows Mobile development team announced via Twitter on May 14 that Windows Mobile 6.5 is "done."
I'm guessing "done" means the latest mobile operating system has been released to manufacturing. But so far there's no "official" press statement or word to that effect.
Update (May 18): Windows Mobile 6.5 has been released to manufacturing, a corporate spokesperson confirmed Monday.
Microsoft officials had hinted that the company was planning some kind of "launch" of Windows Mobile 6.5 last week during TechEd 2009. The Softies subsequently altered the Windows Mobile blog post that mentioned this, by removing the word "launch" from the original post.
Launch or no launch, here's what the May 14 tweet from the Microsoft dev team said:
The first Windows Mobile 6.5 phones are expected this fall. Microsoft is working on the successor to this release, which is known as Windows Mobile 7, but officials have now taken to saying that Microsoft "have not announced anything beyond Windows Mobile 6.5."
Windows Mobile 7 phones, last I heard, were slated to arrive in the first half of 2010. Microsoft officials have been working on Windows Mobile 7 for several years. This is the alleged Windows Mobile 7 chassis spec list.