The only original PSP titles from Square-Enix that I know of are Crisis Core and the recent, Dissidia: Final Fantasy. After that, they have remakes of FF 1 and 2, remakes of the first 2 Star Ocean titles (just announced), a port of Final Fantasy Tactics, and a port of Valkyrie Profile: Lenneth.
Add Reverent Wings and Children of Mana to nitsu niflheim's list of original DS titles above.
Support seems pretty even. And seeing how port happy Square-Enix is, I wouldn't be surprised if they port some of those PSP titles on Wii.