iOS 6.1に対応した最新版のXcode「Xcode 4.6」がリリースされています。
Xcode 
カテゴリ: 開発ツール
価格: 無料
バージョン4.6の新機能はiOS6.1用のSDKが追加されたなど以下の通りです。
• Includes SDKs for OS X 10.8 Mountain Lion and iOS 6.1.
• Code completion heuristics are more accurate, and use an optimized default data set.
• New compiler warnings help identify potential bugs when using ARC and weak references.
• C++11 support for ‘user defined literals’ and ‘unrestricted unions’ features.
• Debugger can inspect elements within NSArray or NSDictionary objects.
• Analyze now performs deeper cross-function static analysis of Objective-C and C++ code.
• The number of indexing passes is reduced due to improved dependency checking.
• Additional bug fixes and stability improvements.
