WindowPhoneHacker have been teasing a new app which they call Mass Storage which would allow a user to transfer files to and from their Windows Phone.
The app has however nothing to do with USB Mass Storage mode, and actually transfers files over a data network with WindowsPhoneHackerâ€™s servers mediating the connection between the phone and a PC. A nice advantage of this method is that the transfer should work with any PC with a data connection without the need to install client software on that PC. The disadvantage is that both the PC and phone will need a working data connection, which may be a problem in some locations.
Jaxbot notes the app does not need root privileges to run, so it should presumably be OK to submit to Marketplace, which is exactly what we hope they do.
Read more about the app at WindowsPhoneHacker here.