The fastlane suite of tools has been around for a while now but this week Felix Krause shipped 1.0. The release includes OS X support, better documentation, auto update and a few other smaller features and bug fixes. Even if you don't want to automate an entire CD process, there are a whole load of useful individual tools in here.
While developing Buildasaur, Honza Dvorsky ended up learning more about Xcode Server than anyone outside the development team should. In this post, he takes a comprehensive look at the structure and architecture of Xcode server and bots. Even if you probably won't end up digging this deep yourself, it's an interesting read.