Its really limited to just a few colours, a place to pop your iPhone and a specially designed app to control some stuff in the car. Not that you really need it, but, cuz you can.
According to 9to5mac, You can connect to the Beetle wirelessly or via the docking station thats built into the car, and using the following apps for further integration:
Spotify: lets users stream media such as new songs, customized playlists or online radio stations into the Beetle. Those who wish can post their favorite music directly to friends. In addition, users in the Beetle can switch between “Spotify” and “iTunes” at any time.
Expert: offers five functions which make the iPhone an extended on-board instrument of the Beetle, such as a G-Meter (for measuring lateral acceleration), oil and coolant temperature gauges for the engine, a chronometer, and a compass.
Trainer: can be used to compare driving times, distances, and fuel economy values for different routes between any two destinations. Here, too, tips can be posted via social networks like Twitter and Facebook—such as which route is faster to the office.
Reader: lists the latest messages from social networks like Facebook, and reads iPhone messages aloud.
Postcard: Sends the current location of the Beetle to friends as a digital postcard with a map motif.
Photo: Sends photos taken inside the car to numerous social networks. Simply activate it, and the app does the rest.
Milestones: Available when the smartphone is undocked. Rewards its users with virtual “milestone stickers” for the Beetle when certain tasks have been completed.
It’s essentially the same functionality as Siri Eyes Free coupled to a basic car data interface and a few cute Beetle-specific apps like the postcard feature, but it will likely appeal to the car’s target market – people who like cute things – and to be honest, I guess it is kinda cutesy.