Most of the settings that you'll find in the app have been a part of Android for a while, but they just haven't had a centralized location before. You could have gotten to the same settings page via the Google Maps settings, or Google Search settings, but now there's a dedicated icon in your app tray to make it easier to find. The Google Settings app was pushed out (similarly to how the Play Store is updated) in a background update of Google Services 3.0.
In addition to the old options to control your location monitoring, search options, and ad display options, the Google Settings app gives you quick access to Google+ settings and control over apps you've signed into with Google+. It's odd that voice settings and Google Now settings haven't been pulled into the app, but maybe that will come when a higher proportion of Android devices has Google Now.