(We got our review copy this morning and it's amazing.) Developers Ready At Dawn are already thinking about moving on from the PSP though. It's the platform that's made the studio's name, but they have bigger ambitions. That's fair enough, they're a very talented group.
The studio's announced that they're working on a new "action-adventure" game based on original IP. There's no word on platforms yet, but it's being developed with Ready At Dawn's own custom engine, which apparently supports virtually all platforms out there. So we can probably expect and XBOX 360/PlayStation 3 title out of the team, but don't discount the Wii or iPhone either.
Obviously it's still early days, so no date or solid information yet. There's more on Ready At Dawn and God Of War: Ghost Of Sparta through the link, though.