Sega has announced that the Phantasy Star Universe servers for the PS2 and PC versions will be closing on 31 March 2010.
If you still want to play, subscribe soon, as no new subscriptions will be available after 29 January. Players who are still subscribed by then will get to play for free until the servers shut down.
To add insult to injury, the Xbox 360 servers will remain operational, and still receive updates and support.
Thanks to meteor9 for the heads up on this news.
EDIT: You do not need to renew your subscription! What was meant was having an account on the game, which Sega terms as "a subscription", even if it's not active. So if you've paid for a subscription in the past, you're good to go.