Join android devices with Wi-Fi Networks using Qr Codes!
Generate a QR code containing a network password, using (for instance) QRStuff's code generator (http://www.qrstuff.com/) or automatically using easywifiaccess app for Windows pcs (http://sourceforge.net/projects/easywifiaccess/). Then, just scan the code with this app to join the network.
The app also can save your network's Qr code, to share your connection with your friends!
This app requires Barcode Scanner to run (https://play.google.com/store/apps/details?id=com.google.zxing.client.android&hl=en)