process of becoming a masters swimmer

I'm 18 and thinking about entering some masters meets this summer. How do I sign up to become a masters member. I'm not on a team, I'm just going to be unattached. I live in VA, so does that mean I have to sign up for the colonial zone, or is it just national? And when I do become a memeber, can I do meets outside of my zone? The first meet I plan on doing is the Terripan Cup on july, 8th. So how soon do I need to register for membership?