Apple released Google+'s iPhone app yesterday, and it is currently the top free app in the iTunes App Store.
The app has been up for a mere 24 hours, and the service itself is still only in beta form.
VentureBeat reports that Facebook's mobile app is currently in the 15 spot, and Twiter is in 37th today.
U.S. & World
Google would like you to know if you downloaded the iPhone app in the first hour and 40 minutes, it may be buggy, and you should update the app with the less buggy version.