This makes sense, since Continuum Shift II is just the original BB:CS with the console DLC added and a bunch of re-balancing, which can be handled through patches on consoles. The PSP only has the series' first title, Calamity Trigger (review), currently.
The new PSP game will support the same modes as Calamity Trigger, but will add a new mode called "Abyss" that Dengeki speculates could be a type of dungeon-crawling mode with some character building functionality. The game's multiplayer mode will also support four players: two fighting and two watching.
This is a Japanese release right now, but all of the BlazBlue games have historically made their way over through publisher Aksys. An Aksys representative told Shacknews that "it's too early to say" if the company will be bringing this release stateside.
Awesome! Continuum Shift is so much better than Calamity Trigger.
Hopefully they bring it stateside.