Xcode 3: mkdir -p ~/Library/Application\ Support/Xcode/Color\ Themes cp Xcode3/Railscasts.xccolortheme ~/Library/Application\ Support/Xcode/Color\ Themes Xcode 4: mkdir -p ~/Library/Developer/Xcode/UserData/FontAndColorThemes cp Xcode4/Railscasts.dvtcolortheme ~/Library/Developer/Xcode/UserData/FontAndColorThemes Based on Ryan Bates' Railscasts Textmate theme