While I do believe that Neville will play a role, I don't believe he is the one the prophecy is about. In "Order of the Phoenix", Harry questions Dumbledore as to whether the prophecy is about him or about Neville.
"Then - it might not be me?" said Harry.
"I am afraid," said Dumbledore slowly, looking as though every word cost him a great effort, "that there is no doubt that it is you."
"But you said - Neville was born at the end of July too - and his mum and dad -"
"You are forgetting the next part of the prophecy, the final identifying feature of the boy who could vanquish Voldemort.... Voldemort himself would 'mark him as his equal.' And so he did, Harry. He chose you, not Neville. He gave you the scar that has proved both blessing and curse."
"But he might have chosen wrong!" said Harry. "He might have marked the wrong person!"
"He chose the boy he thought most likely to be a danger to him," said Dumbledore. "And notice this, Harry. He chose, not the pureblood (which, according to his creed, is the only kind of wizard worth being or knowing), but the half-blood, like himself. He saw himself in you before he had ever seen you, and in marking you with that scar, he didn not kill you, as he intended, but gave you powers, and a future, which have fitted you to escape him not once, but four times so far - something that neither your parents, nor Neville's parents, ever achieved."
"Is ice hockey hard? I don't know, you tell me. We need to have the strength and power of a football player, the stamina of a marathon runner and the concentration of a brain surgeon. But, we need to put all this together while moving at high speeds on a cold and slippery surface while 5 other guys use clubs to try and kill us. Oh, yeah, did I mention that this whole time we're standing on blades 1/8 of an inch thick. Is ice hockey hard? I don't know, you tell me. Next question."