Video PlayBook 101: How to setup and use Wi-Fi File Sharing on the BlackBerry PlayBook
Being that there isn't much help documentation on the process or setup just yet, I did have a bit of trouble getting going. When you connect the PlayBook to your computer for the first time with a USB cable, it should install the necessary drivers for both standard connected file sharing and Wi-Fi File Sharing (the PlayBook doesn't just show up as a USB-styled flash drive). From there you should be able to access the PlayBook as a network drive without using a USB cable, as long as it's on the same network as your computer. I didn't have much luck with the setup, so I took a different route and added the PlayBook manually. In the video above I explain how to get the PlayBook connected as a shared drive with just a few easy steps.
From there you will be connected to the PlayBook and it will show as a shared drive on the network. Now you can drag and drop files to/from the PlayBook without ever having to connect directly to the device. When Wi-Fi File Sharing is enabled, the PlayBook will be "listening" even when the display is off. So that means when your PlayBook is in standby in your backpack or briefcase or desk drawer, you can still use Wi-Fi File Sharing without having to do anything on the PlayBook itself. This is by far one of my favorite features of the PlayBook now. Being able to get files on it without having to worry about a USB cable or even where the device is (as long as it's still on the same wifi network) is a huge bonus. While I haven't tried it on a Windows PC, it works essentially the same (anyone who has tried it please leave a comment and let us know how it worked!).