There's also that new Ace Combat (Joint Strike?) coming in summer. I'm sure we'll see lots of niche stuff from NISA, XSEED, Atlus USA and others as well (Absolute Hero, Persona 3 Portable, Knights in the Nightmare, possibly Falcom stuff, etc).
Western developers and publishers seem to have dropped PSP almost entirely though. We won't really know for sure until E3 though.