Google Authenticator hit version 2.0.0 with the latest update, finally bringing Retina display-ready graphical assets to the app. There is a major bug in the procedure, however, as updating appears to erase all settings and tokens.
As for the app itself, functionality has not been changed, though the UI has been revamped with larger text and an overall aesthetic closer to Google's other iOS titles. The feature set remains the same, with automatic setup via QR code, multiple account support and time-based or counter-based code generation.
Google Authenticator comes in at 1.1MB and is a free download from the App Store, though backing up account data is highly suggested before installing.