Letters in Xcode Project Navigator I want to know the meaning of the letters in the project navigator in Xcode; (Ms &amp; A)
These are for source control. M stands for Modified. A stands for Added. This is so you know what files have changed since the last commit of your project.

It's all explained on this support page http://developer.apple.com/library/mac/documentation/ToolsLanguages/Conceptual/Xcode4UserGuide/SCM/SCM.html