The DNG converter 6.4 has been released, http://www.adobe.com/products/dng/ with support for many new cameras, including:
Note that it is the last version to run on Power PC Macs: http://blogs.adobe.com/lightroomjournal/2011/03/dng-converter-6-4-last-to-support-powerpc- mac-systems.html
Also released today: The DNG codec 1.1 that now supports the 64bits version of Windows 7, but does not support Vista anymore.
Finally, the DNG Profile Editor beta 3 is out too, and has also been updated to address bug fixes and support DNG files utilizing the updated DNG 1.3 Specification.
I just downloaded and installed this version on Windows 7 Home Premium 64bits.
I can report it works great with my Raw DNG files, from camera: Pentax K-m/ K2000.
Probably also with all other Pentax camera's.
Works fair on my Win7 x64 install with Pentax created DNG's. The rendering of the thumbnails in Windows Explorer is pretty slow but they eventually get there. Hopefully as more thumbnails get cached speed will improve.