Phantasy Star Online celebrates 10 years as a series this year, and Sega took this opportunity to announce a brand new game in the series - no other than Phantasy Star Online 2. The game is being developed for PC, but there's really no other information available. There's a trailer currently available on the official Phantasy Star Portal, but it shows absolutely nothing from the game.
So you'll just have to wait patiently for more information to be released. I got a feeling our own Bengt Lemne is bouncing up and down inside right now.