Originally posted by 528
You have to go back and press O (or whatever crouch is) and then jump quickly just as you fall off. (i.e. be crouched on the windowsill and then jump as you're about to fall)
you dont need to jump ( or atleast i didnt ) just tap O as fast as you can while moving back slow then just as your about to fall let go of all the buttons and up you go , but this is really hard on ps3