According to Whitney Tidmarsh’s talk today, D6.5 is slated for the end of July. An official announcement should be coming next week.
What does this mean? It should be on the download site by the second week in August. The download site is run by a 3rd party, so sometimes it takes a bit to get everything updated.
If you work with your account rep, you can make sure that you get it on the actual release date.