Some unsecured wireless networks try to hide their SSIDs to prevent outsiders from connecting to them. This is the most easiest wireless network to hack.
Simply google Commview for wireless networks, download the software and follow the instructions to install.
After installing it, run it and scan for wireless networks in your range. When the search is complete, the SSIDS of the networks will be typed against their channels. Just copy the SSId!
Afterwards connect to the network, input the SSIDS and voila!! U r connected