Pastel is an Xcode 4 colour and font theme, designed for (Objective -)C , originally based on the Railscast TextMate Theme for Ruby, which in turn, was based on the Idlefingers Theme.
To install the theme move it into ~/Library/Developer/Xcode/UserData/FontAndColorThemes/, creating any directories you need to along the way.
At some point, if I ever get round to it, I will create a proper installer. For now though, you will have to move it yourselves.
I have purposely not chosen a font for the theme, I have set it to use Xcode's default Menlo. It is easy enough to change it to your preferred font in the Fonts and Colors pane in the Xcode preferences.
I have added a quick screenshot which I feel is fairly representative, if anyone has any suggested open source files that would be a good demo to screenshot do say.
