"Sonic Adventure and Crazy Taxi will be the first two classics made available," the company says, "with Sonic leading the pack in Fall 2010 for the 11th anniversary of the launch of the Dreamcast in the United States." According to the Sega PressVault, both titles are due to arrive in Q3 2010, so between July 1 and September 30, 2010. The company boasts that the re-releases will "incorporate all-new enhancements and features such as high resolution visuals and surround sound," plus online leaderboards and integrated support for Achivements (Xbox 360) / Trophies (PlayStation 3).
A re-release of Jet Set Radio / Jet Grind Radio has been rumored, but not confirmed.
oh dreamcast :)