Xcode Find and replace in all project files

I need to replace NSLog with DDLogVerbose in all files in the current project I am working on… What is an easy method to do this? (the search navigator only has search in it).

Also I need to add a line at the beginning of all .m files. How is this done quickly? (There are over 500 such files.)

Here are some pictures. In the toolbar search, you have to press 'Find' then a menu appears – pick replace. Now you can replace project-wide.