Atlus: Currently researching the hardware, but not developing specific games yet.
Bandai: Considering development seriously.
Capcom: Considering development seriously.
Chun Soft: Considering development seriously, particularly the prospect of new "Sound Novel" games.
D3 Publisher: Considering development seriously.
From Software: According to its policy, From is researching the PSP as it would any hardware.
Irem: Considering development seriously.
Jaleco: Still evaluating the prospect of PSP games.
Kadokawa Shoten: No plans for PSP development at this time.
Koei: Games are in development, possibly for launch.
Konami: Multiple titles are in the works for the system's launch.
Namco: An announcement is likely at E3.
Nippon Ichi: Looking to release a title shortly after launch.
Sega: Working on titles -- an announcement is likely at the Tokyo Game Show.
SNK: Still evaluating the hardware.
Square Enix: Surprisingly, Square Enix claims to still be evaluating the hardware.
Taito: A PSP title or titles is in the planning stages.
Tecmo: Undecided as yet.
Tomy: Still evaluating the hardware.