Well, it's very hard to conclude guilt or innocence from only the testimony of the defence, and it is very clear that Plato intends that people reading this report conclude that Socrates was innocent (perhaps just lacking political savvy in his defence).

Certainly Socrates did little to endear himself to the high-ranking citizens of Athens, which also did little to help his cause, and combined with his apparent resolution to go to his death (shown in other writings more clearly), most likely as a way to ensure he would be remembered by those he had most affected, and that his approach to inquiring everything would be maintained by his pupils.

I wouldn't be surprised if Socrates were in fact guilty of heresy (which I believe the main charge was, although my memory is a little hazy on that mark) - certainly Plato's recordings of his dialogues suggest that he had little love for the Gods, and his approach to various issues challenged a lot of the beliefs associated with the Gods. Certainly Socrates was guilty of being an irritation to those he engaged in dialogue - very much like a prankster is generally not appreciated by those who end up as the butt of his jokes. Whether his crimes warranted the death penalty, I doubt that they did - however, Socrates' decision to call the bluff of the prosecutors and suggest he should be sentenced to pay a moderate fine instead does not seem fitting punishment either - exile or imprisionment seem more appropriate punishment, but since they were not made options, they could not be considered. Overall, I believe the outcome, while regrettable, was nonetheless just for what was made available to the jury.