Phone stopped connecting to Wireless
You could try Settings -&gt; General -&gt; Reset -&gt; Reset Network Settings.

From the docs:


  This will reset all network settings including:
  
  
  previously connected Wi-Fi networks and passwords
  recently used Bluetooth accessories
  VPN and APN settings
  


More information about troubleshooting WiFi networks is available here:
http://support.apple.com/kb/TS1398