Agree with corpsman33. If you are thinking you might do HPSP, start the process NOW (ideally a couple months ago!). It takes FOREVER to get things in (medical, security clearance, motivational statement, an "application" that is-no kidding-much longer and worse than AMCAS or AACOMAS, etc). At this point in the game, I have three interviews coming up (2 in a week, and one in January), so I'm hopeful, and really trying to get all my paperwork together to send in once I have an acceptance.
That being said, I'm not so sure that HPSP would give you any kind of a leg up in the acceptance realm. #1-you wouldn't actually HAVE a scholarship yet and #2-I don't think that schools consider the ability to pay for schooling when they weigh applicants.