Your Tech Blog is liveblogging the event too and writes:
Today, a third kind of notebook called MacBook Air being introduced. World's thinnest notebook. 0.76" 13.3-inch screen, LED backlight with instant on. Full-size keyboard with backlighting. Large trackpad with a variety of gestures for panning, rotating, zooming (with iPhone-like pinching), etc.Via News Cut.
Update: And there it is, Apple's guided tour of the Macbook Air. Nice!