Submission
You may submit your application to schools without an MCAT score, however, most will refrain from reviewing your application until your scores arrive. I applied after I got my scores, so I knew what schools I stood a chance getting into. You must pay for each school you apply to, and almost all will send you a secondary application. I ended up applying to nine. But I've also heard of people gunning for one school. Everyone I know that met the school's averages or had better, that did this, - DID - get into that school. I don't advise doing this though, I thought they were crazy.
And the equation -
Here is an equation that some people live by:
(Your Cumulative GPA * 10) + MCAT score = Competitiveness score
X > 70 = highly competitive (i.e. 4.0/30, 3.6/35)
70 > X > 65 = competitive (i.e. 3.7/30, 3.5/31)
65 > X > 60 = least competitive (i.e 3.5/30, 3.5/28)
60 > x = needs work :( (i.e 3.2/27)