WPCentral has revealed an interesting hack on the desktop side which allows full access to the media libraries on on a Windows phone 7 device.
The instructions are as follows:
Now you will modify three entries (note, if you have multiple WP7 phones, you have to do it for each one)
The device, and folders for music, video and images should now show up in explorer, and to enable modifying the files the Zune desktop software simply needs to be closed.
Other files can also be placed there, but will not be accessible on the device, allowing the use at least of the smartphone as a USB drive.
Thanks Mark for the tip.