According to the resume of composer Timothy Williams, the God of War series will continue with God of War IV, and he's supplying the tunes. The game was spotted on Williams' listed projects, and a whirlwind of giddy speculation has swept cleanly through the Internet since.
This isn't the first bit of God of War IV news we've seen. Almost exactly two years ago, the game was mentioned, and more recently PSM3 claimed it would arrive this year, with co-op included.
All signs point toward this game being real, but that's hardly surprising considering how popular Kratos' violent exploits are. Expect this new dribble to become an outpouring in the run up to E3.