With major D-1 programs, there is a HUGE amount of communication that goes on before July 1 prior to senior year, even before Sept. 1 of junior year.
A player can:
Call the coaches and if they answer, talk all he and they want. (But if you leave a message, they cannot call back, because they cannot initiate a call until July 1 and then only once/week.)
E-mail 'til the cows come home. (Sometimes a coach will agree by e-mail to sit by the phone waiting for your call at an appointed time.)
Have your high school and/or travel coaches talk to the coaches at target colleges for you.
Talk to them on their campuses -- at camps or "unofficial" visits
There also was an awful lot of texting going on until the recent imposition of the texting ban -- the one NCAA move that we who pay the cell phone bills truly applauded! (E-mails are free!)
Bottom line, you don't have to wait for the Sept. 1 or July 1 dates to get going. Sept. 1 of junior year is still very early in the process, but it's probably not adviseable to wait for July 1 of the following summer to see if the phone rings.
As one concrete example, I can tell you that we just had an "official" visit at Wake Forest. This particular weekend was not so much to recruit as to introduce the committed HS seniors to each other and to players already there and on the team. There are 8 2008's already committed and the coaches are only looking to fill a few more slots. I can assure you that not one of these 8 committed kids waited for July 1 to roll around to get started. The guys under consideration for the remaining slots didn't, either.
This means that in the case of this one school at least, there isn't a whole lot of opportunity left for those who may have waited until now to get started. And I don't think Wake is unusual at all; what they are doing is what I see going on with most of your major D-1 programs. So if you're a 2009 or younger, keep this in mind; you are not safe simply to "wait and see". The rest of the world will move ahead without you.
November may be the "early" signing period, and there may be an April signing period as well, but the fact is that after November a whole lot of teams will have filled all of their openings. Not everyone, mind you, but a lot.
I would suggest that at the very least, by fall of junior year a player who thinks he has D-1 potential should be researching schools and programs to determine maybe 5 that he intends to look at more closely. Then contact those 5 and see if you can generate interest. Try to get them to come scout your spring games, or ask if they're coming to a showcase or tournament you may be playing in so they can see you play. Give them your HS coach's contact info so they can start investigating whether you are the real deal or someone with an unrealistic impression of your own abilities.
By the time the following summer rolls around, you want to have a very firm idea of where you stand and whether you are getting anywhere with your top 5 -- or whether you need to move on to other potential schools. If you are seen as the type of player to play at the level of the schools you contacted, you should be getting at least some serious interest. If you have overestimated how others see you, then you need to get honest with yourself in a hurry before you miss out on the next tier of choices.
Bear in mind that this is the time table for major D-1's. Some mid-majors will leave openings to fill over the winter or even into the spring of senior year, and will basically pick up the kids who get passed over by their dream schools. And D-3's will get into the picture very late many times, because they know that a kid may well not look at them at all until he's sure he can't land a scholarship deal somewhere.
So, there are still lots of opportunities for kids late into senior year and even in the summer following some times. But if you want to get your top choice, or one of your top few choices, get cracking early.