If your car is a frequent business-trip companion, consider the Autonet Mobile router. Installed into the trunk, it creates a personal Wi-Fi, 3G hot spot anywhere.
Multiple devices can share the Internet without slowing its speed. You connect wirelessly to the Autonet access point in exactly the same way you would for a stationary access point. Speeds will depend on the data size as well as the strength of your cellular signal, but reports are its competitive with portable, handheld devices like an iPhone.
Autonet Mobile is about to become much more common: It’s now an add-on option for Cadillac, Chrysler, and VW. The monthly subscription fee is $29 a month.