Monster Hunter 3 tri~ will remain exclusive to the Wii. 1UP reports that Capcom has come forward to dispel rumors that the title would make its way to the PSP as well, writing on the game's official website that despite comments made in "a certain magazine," the hotly anticipated 2009 release "utilizes the unique features of the Wii to their fullest, and development continues with the intention of creating a Monster Hunter never before seen."
While not exactly a ringing endorsement for multiplatform support, you can blame the doubting looks on our faces on Capcom's track record with platform exclusivity. After all, we eventually played Resident Evil 4 on the PS2 and Monster Hunter 3 itself was at one time announced for the PlayStation 3. Clearly, the only thing for certain here is that Capcom likes money.