The Boss's official site is one of the better official musician sites out there… a great resource for lyrics and album art, in particular.
Bruuuuuuuuuuuuuuuuuuce has a huge legion of fans all around the world. Backstreets is their go-to virtual gathering place, and thus home to some of the most engaged and informed E Street Band commentary (and the best Springsteen message board) around.
Springsteen's official home at the Rock n Roll Hall of Fame offers a nice brief biography.
America's premier music magazine opens up its archives to offer a wealth of Springsteen material dating back more than three decades. Great stuff!