Good news, the Internet! Your "bring Assassin's Creedto PSP" petitions totally worked. SCEA announced during Destination PlayStation today that the game will appear courtesy of Ubisoft on Sony's portable later this year. In fact, your efforts were so effective, Sony's releasing an Assassin's Creed-themed bundle, though the only component they're talking about now is a Piano Black PSP.
SCEA stopped short of actually saying the move was thanks to the overwhelming, petition-generated e-pressure, but you'll always know the truth in your hearts.