On April 1st, 2007, Sonic Team will officially be shutting down the Gamecube and Dreamcast servers as seen in this announcment. The servers will become free-to-play on March 1st, 2007 for a one month period. Also, the 90 payment option will be discontinued on December 8th and the 30 day option on January 29th. Listed below is the versions of the game that will be affected by this anouncement:
DreamcastVersion 1
Version 2
[*]Gamecube Episode 1&2
Episode 1&2 Plus
Episode 3 The XBox and Blue Burst servers will remain in operation for the forseeable future. Credit goes to Renamon for spotting this update and EspioKaos/Arislan for providing translations. You can share your reaction in our Phantasy Star Online forum.
Source : http://www.pso-world.com/