If I have a Warlock w/ PBS, and he uses his Repelling Blast on 2 or more opponents (within 30 feet for himself), will he get the benefits of PBS? I would assume yes...
I don't have the book handy, so I can't read the description of Repelling Blast.
As long as an attack roll is required and it is a ranged attack, Point Blank Shot should apply. If the attack does not do damage, the bonus to damage would not apply, though.