Well, So far Sega has annouced a ton of new games, but very few for the gamecube. I think this megaton thing may not include much sega support after all. PS2 is getting the majority of sega support.
Also:
Sakura Taisen PS2 - February 27
Initial D Special Stage PS2 - March 27
SEGA AGES games announced for PS2:
Space Harrier
Fantasy Zone
Phantasy Star
Golden Axe
Monaco GP
Alex Kidd's Miracle World
Gain Ground
Bonanza Brothers
Streets of Rage
Tant-R (thanks fen!)
Phantasy Star 2
Virtua Racing
Phantasy Star 4 (thanks fen!)
Last Bronx
EDIT: Also announced for XBOX:
Rent-A-Hero No. 1
Illbleed
Dynamite Deka 2
Blue Stinger: Premium Cut
EDIT: Also announced for GAMECUBE:
A baseball game. Possibly the Japanese Home Run King.
Also:
Sakura Taisen PS2 - February 27
Initial D Special Stage PS2 - March 27
SEGA AGES games announced for PS2:
Space Harrier
Fantasy Zone
Phantasy Star
Golden Axe
Monaco GP
Alex Kidd's Miracle World
Gain Ground
Bonanza Brothers
Streets of Rage
Tant-R (thanks fen!)
Phantasy Star 2
Virtua Racing
Phantasy Star 4 (thanks fen!)
Last Bronx
EDIT: Also announced for XBOX:
Rent-A-Hero No. 1
Illbleed
Dynamite Deka 2
Blue Stinger: Premium Cut
EDIT: Also announced for GAMECUBE:
A baseball game. Possibly the Japanese Home Run King.