One of Sony's upcoming PSP games, Resistance Retribution, will utilize a newly developed technology called "PSP Plus." The feature will allow players of Retribution to connect their systems to the PS3, in order to enable use of PS3 wireless controllers. Using the DualShock will enable dual-analog control in the game. In addition, rumble will be supported. This potential use of connectivity was hinted at in a patent filed over a year ago.
Other games may be able to potentially utilize PSP Plus -- however, it is currently a Retribution-only tech. Stay tuned as we reveal the exciting additions PS3's Resistance 2 and PSP's Resistance Retribution will bring (together!).