There are few things that are more of a drag, in the mobile device world, than having to find where you left your micro USB cord to plug in your device just to copy a couple of files over to your computer. Most of the time wireless services like Dropbox help alleviate this need. For the times that those aren't enough, Droid NAS can turn your device into wireless storage. Provided you use a Mac or another Android device to access it. Once connected, your Android phone or tablet will show up as a Bonjour device.
The app uses the SMB protocol which, unfortunately, Windows cannot connect to via a non-standard port.