I´m getting this error in XCode:
2013-08-23 14:36:18.284 Tell The DJ[14955:c07] ERROR: Plugin \'Device\' not found, or is not a CDVPlugin. Check your plugin
I encountered the same issue. I have followed the solution given by Jeffrey Van Alstine. This is my script for building and testing an iOS app developed using Phonegap 3.0/3.1.
#!/bin/bash
echo "Killing xcode..."
kill $(ps aux | grep 'Xcode' | awk '{print $2}')
rm -r platforms/ios
rm plugins/ios.json
phonegap build ios
open platforms/ios/*.xcodeproj
Save it as a bash file, for example, ios.sh into your working directory (directory that contains www folder) and run ./ios.sh