On Air is a free Android application that turns your Android phone's storage into a Wi-Fi accessible drive for easy file transfer, syncing, and more.

On Air is an easy to set up application that turns your Android phone into a Wi-Fi storage device allowing you to easily and wirelessly access your files. Because the interface is very spartan and icon-based it's easy to overlook the configuration options and jump right to pressing the big button.

When you first run the application resist the urge to mash the huge power button in the middle of the screen and do the following instead. First, tap the icon in the upper right corner of the screen, that's the toggle which allows you to switch between ADP, WebDAV, and FTP. For our test we used FTP. Second, press the menu button and open the preferences window. Here you can change the color of the button (we changed it from red to green) and you can lock the 4-digit PIN password. Since we're only using this application on our private Wi-Fi network we opted to lock the PIN so we could create a simple FTP shortcut; for increased security if you're using it away from home you can leave that option unchecked and On Air will generate a new PIN every time you turn it on.

The only complaint we can log against the application is that, on our Nexus S test platform, the giant button that turns the server on does not turn it off. . Either it's just an issue with our test phone or the button doesn't actually turn the server off which would be an annoying oversight. Instead you have to hit the Back button on your phone to kill the session (or kill it in a task manager). Otherwise it functions exactly as promised and allows us to leave the phone plugged in and charging anywhere in the office while still enjoying access to our files.

On Air is free, Android only.

On Air (WiFi Disk) [Android Market]