Figured this out earlier today:

I highly recommend backing up these registry values before modifying anything. If you don’t know how to do that, I don’t recommend that you even attempt this right now =)

1. Make sure your Zune is not plugged in and your Zune software isn’t running
2. open up regedit by going to the start menu and selecting “run”. Type regedt32 and hit “OK”
3. Browse to HKEY_LOCAL_MACHINE\System\ControlSet001\Enum\USB\
4. Search for “PortableDeviceNameSpace”. This should be contained in the Vid_####&Pid_####\########_-_########_-_########_-_########\Device Parameters within the above …\USB\ The ##’s listed here will be numbers and letters specific to your Zune
5. Change the following values:
   • EnableLegacySupport to 1
   • PortableDeviceNameSpaceExcludeFromShell to 0
   • ShowInShell to 1
6. Plug in your Zune, and make sure the Zune Software starts up.
7. Hopefully at this point you can open up “My Computer” and browse your device, though it does NOT show up as a drive letter.

Right now I can access it both as a harddrive and sync through the Zune Software.

[Edit: This was first posted here and ZuneBoards.com after I figured it out. For more information, check out ZuneBoards.com!]

If you can’t use WPA2 on your XP SP2 computer, try this update:

http://support.microsoft.com/?id=893357