Make a video ASAP and send it out with, some stats (if you have any), travel/scout teams you've played for, coach's you've played for who may have some words of reason (not you little league coach). Put in your weight, height, position, GPA and SAT or ACT scores. Good times, such as velocity or 60 time. If you've applied to any of these schools and have been accepted let them know.
But the most important is if you're hoping for something higher than the JUCO level...unless you get a scout out there watching another guy and you catch his eye...no big programs will just take a players word they need to see something that will cause them to be interested. Or if you have a real trustworthy coach of high stature who can put in a good word or has some type of connects that could help too. But if your serious about this get a video together, you don't need a proffessional one...just tape some groundballs, some batting practice, some soft toss and input some game swings. Just get your friend or dad to help you out with it...editing really isn't too difficult.
Best of luck!