All three versions--PC, PlayStation 3, Xbox 360--are expected to be released then.
The game's retail debut will be prefaced by an Xbox 360 multiplayer beta that kicks off March 8 and runs through the month. There'll be various ways to get into the beta--we've already given away 900 keys--but just to be safe, you may want to sign up over on the official site (look for the "Blur Beta" box in the lower right-hand corner).
As for what that beta will contain, Bizarre provided the following rundown:
14 cars in four different car classes (A through D). Some are nippy (Koenigsegg CCX-R), some are beautiful (Volkswagen Scirocco), some are tough (Land Rover Defender SVX), and some are just plain cool (Chevrolet Camaro 1969). 4 different race tracks: Barcelona Gracia, Tokyo Shutoko, Amboy, and Long Beach Docks. Each provides a totally different racing experience, from wide-open off-road races to tight, technical inner-city tracks. My personal favourite is the Docks - it's got alternate routes through shipping containers, and one particular crossover which is going to ruin a few bumpers... Twitter support. You can enter your Twitter credentials and share a Tweet or two DIRECTLY from the game. And it won't spam your account either - nothing is posted without your say-so. Just hit the left-bumper from anywhere in the menus to bring up the "Share" menu. ...And of course, 8 meaty power-ups. These really are what make Blur different to every other racer out there. They're so important that we've built a brand new section of our website to tell you about them.