This is interesting
Travis-CI is hosted continuous integration and deployment, using Mac OS X. It integrates with GitHub and supports a fair number of languages. So, you can test and deploy Mac targets without needing Macs of your own.
The big challenge for some companies is letting their source code leave their walls, because obviously this is going to be building your source on machines you don’t control. But I think that attitude is going to die out over time, as people realize that it’s the writing of source code that is where the value is, not the source code itself.
Travis uses xctool to drive XCode instead of xcodebuild.
Another piece of Travis I think comes from Sauce Labs