In the latest evidence that in-car online connectivity is gathering momentum, Subaru said Friday that it is offering Wi-Fi connectivity for its 2011 Outback crossover sport utility vehicle as an official Subaru accessory.

In-car Wi-Fi has been catching on in fits and starts, with individual car owners often purchasing Wi-Fi capability for their cars by modifying products not designed specifically for use by passengers in vehicles.

Using technology by Autonet Mobile, the Wi-Fi service can be added as a port or dealer-installed accessory to 2011 Subaru Outbacks for $500 plus a $35 accessory fee. The service also requires a one-year service subscription at $29 a month.

"Subaru Mobile Internet easily allows users to check e-mail, surf the web, or listen to Internet radio and even stream video and post to social networking sites," Subaru stated in a release. "Multiple passengers can simultaneously use the Wi-Fi connection for their separate devices, including Wi-Fi cable laptop computers, netbooks, smartphones, game controllers, plus the new iPad and iPod Touch models."

Autonet Mobile has pioneered in-car Wi-Fi technology, beginning in 2007 with service in Avis rental cars. The company recently unveiled its CarFi portable wireless router and docking station. The CarFi device allows users to move the router among multiple cars with docking stations. Autonet said the device is targeted at families with multiple cars.

Vehicles fitted with GPS, including fleet vehicles, can easily be tracked using Autonet service.