For GPS fanatics or even just the average driver, March 27 is a big day. The rehearsals are over and Dash Navigation’s Dash Express is ready for showtime. The device—the first Internet-connected GPS unit designed to deliver the most up-to-date traffic data to consumers—begins shipping today on Amazon.com for $399. For this price, the Dash comes with a three-month trial, followed by a monthly cost as low as $9.99 for the cellular connections. We’ve been waiting to try out the Dash since International CES 2007. GPS devices have been flooding the market since then. So what exactly have we been waiting for? The answer is that the Dash is unlike the Garmins and TomToms of the navigation world. Every Dash Express on the road connects to the Internet using a Wi-Fi or cellular connection. When it has a Wi-Fi connection, the Dash searches for larger downloads, such as maps. When it has a cellular GPRS connection, the Dash gets traffic feeds and sends traffic reports back to the service (which Dash calls TruTraffic). The result is almost instantaneous: If you’re cruising down the highway and you suddenly hit a traffic jam, the Express will tell you how long your delay is expected to be, based on how quickly other cars with the Dash are moving through it. The Dash Express will also recommend up to three alternative routes and send your traffic data back to the service so that the driver with a Dash sitting a few hundred yards behind you can have updated information. Oh, and did we mention POIs are nearly unlimited? Dash uses Yahoo search, so users can search Yahoo’s Local directory straight from the device for nearby businesses, products, and services. Dash also lets you register your device to an Internet portal called MyDash. Using MyDash’s Send2Car feature, you czan send any address from the Web or your PC directly to your device in seconds. On MyDash.net, users can also create new search lists, such as “My dog’s favorite parks,” and send them right to the Dash Express.