Originally Posted by FrostNova
MotioninJoy Gamepad tool (DS3 Tool) > Xbox 360 Controller Emulator > Enjoy.
There's also Playstation controller support in pso2 settings but it didn't work for me.
PM me if there's any questions regarding setting up the PS controller i'd be glad to help you out.
So far TERA is the only game I've seen officially support a PS3 controller IN PS3 mode. And even that doesn't work right (buttons 1/2 are switched, as are 3/4, and 9/10/11). However, setting a PS3 controller to Xbox emulation seems to work in nearly every game, its what I had to do for PSO2.