I have heard ideas for a tool like this to find duplicates and unused files in projects bounced around many times but Dragon Forged Software actually went ahead and did it, and very useful it is too.
Kyle Newsome with a detailed look at AppCode. It would be great to see some of the features from AppCode make it into Xcode but I don't think I will ever use AppCode full time, maybe I would feel different if I was coming from Java dev using JetBrains tools.
Need a quick web site for your iOS app? Ben Scheirman has created AppKickstand which gives a cleaner mini site for your app than the default iTunes store page. This would be a great little tool if it supported video for the preview area rather than just a screenshot.