applying to b-school is not just a one day thing, so there's not much of an "apply *before* GMAT".
You should register for the GMAT right now (never hurts to start early), and take it in 2-3 months (after studying). Refer to our GMAT Forums for tips and tricks.
While you're studying, make a list of schools you want to look at. You should have roughly 10-15 schools ranging in the Ultra Elite down to whatever level you believe you're competitive in (use Ask
Accepted.com or Ask MBA Game Plan or just ask any of us to determine your potential ability with a profile).
This way, when you take the test, you know the top 5 schools on our list that you most likely will apply to, and you can send your scores to those schools.
Then the application begins with essays, recommendation letter preparation, and all sorts of crazy stuff. That will take you an average of 1 month per school. Start early, aim for an October submission for all your schools, since it's going to be tough next year!