These files are ports of my Earthworm and Quiet Light themes for Espresso to Xcode. Thanks to Xcode's relatively inflexible syntax definition system compared to Espresso, the port isn't perfect, but the general feel for both themes is intact (at least for Objective-C files; I have not tested these themes with other languages).
Copy the .xccolortheme files into this directory (creating it if necessary):
~/Library/Application Support/Xcode/Color Themes/
Copy the .dvtcolortheme files into this directory (again, creating it if it doesn't exist):
~/Library/Developer/Xcode/UserData/FontAndColorThemes
Both themes are released under an MIT license, so feel free to use them as you wish. If you have feedback/kudos/critique please feel free to contact me directly.
Enjoy!