We've received word that Microsoft has quietly made ActiveSync 3.6 available for download. I've looked at the ReadMe file, and although there is a host of new features listed the only real improvement seems to be support for Windows Powered Smartphones.
The ReadMe file lists several new improvements, but many of these such as the desktop pass through were available with previous versions. It is worthy to note that the download is available at the link below, but Microsoft is still listing 3.5 as the current version.