When the MacBook Pros were first announced people were perplexed by the ExpressCard slot. What are we supposed to do with that?!
Luckily, a number of ExpressCards have been released, and more are coming on the market all the time. Amongst the items one can now shove into one's MacBook Pro (without voiding the warranty) is the Verizon Wireless V640 ExpressCard which allows your MacBook Pro to suckle at the wireless broadband teat of Verizon's network.
How well does it work, you wonder? Derek at 5ThirtyOne got his hands on one and took it for a spin. He reports that OS X has all the native drivers built into it, so installation was a snap. Verizon even supports Macs with a utility that runs in OS X, though Derek recommends just using the builtin goodness since the Verizon app isn't all that great.