How many times have you been working on a computer, and needed a USB stick but only had your phone? With older Windows Mobile 6.5 devices, this was fairly simple – just go into the settings, and change the sync mode. HTC even had a popup in their Sense UI that would prompt when the device was plugged into a computer.
Since the inception of Windows Phone 7, however, one would have to launch the Zune software, and complete the file transfer there using the sync tool; there really hasn’t been an easy way to enable this functionality. Sure, there is a way to do this via a registry tweak, but look through the Zune Software, or on the device, and this feature is absent.
All you will need to use is the Zune software, and .Net 2.0. According to the developer's website, ultimate-networx.net (loosely translated from German), you will need to run the tool as an administrator for it to work correctly. Once it is enabled or disabled, you will need to disconnect the device and then plug it back in. Upon checking drives listed in Computer (in Windows 7), you will see a device listed with the phone model, and files can be dragged and dropped to/from the device at will.
Image source: xda-developers.com