Generally the first day you can apply is in the first week of June. Last year it was June 4th. This year it is June 2nd. You can submit your application without an MCAT score, but your application will not be complete. I'd suggest having a score before the submission date. Get it over with and out of the way. Also, if you take it earlier, then you will have more time to retake if need be. I'm a fan of the January test (although I am biased). I had the fall semester to semi-study without worrying about other application stuff and then Winter break to really study for it. My test was only 3 weeks into my new semester so no assignments or anything had started piling on yet. Also, if I hadn't done well I could have retaken and still had my scores before application time. There are dates in March and April that would get you your scores before June so those are options, as well. Additionally, you could take it this summer and get it completely done and over with before you start another school year.
Whenever the 2010 test dates are released just be sure to look at the estimated score release date. That way you'll know whether or not you'll get them before June. Generally, scores are released 30 days after the test date though.
