SRH,
First I want to applaud your son for attaining good grades and good test scores.
I have two sons in college, a 2004 grad who had average grades and scores, and a 2006 grad who was in the 98-99th percentile on PSAT and ACT. The 2006 definitely had more options for college!
Second I want to say that my oldest is playing baseball for a D3 college, and the advice given above is correct. Many D3's do not have much of a recruiting budget and will not recruit your son unless he first lets them know he is interested in their school. Make sure he plays on a summer team where he will get playing time, and then start contacting colleges at the end of the summer. I'm not implying that because he is not getting varsity innings as a sophomore he won't have options for DII or DI, but just sharing our experience with D3 recruiting. My 2004 son is very happy with his school choice. (He is a junior this year, but redshirting this spring because of a shoulder injury.)
BTW, like your son my 2006 also received a flood of academic recruiting letters after the PSAT, which continued through his senior year. He did not end up receiving a large academic scholarship because he attends a selective university where virtually all the students admitted had a very high level of achievement in HS. But this excellent university (U of Minnesota) costs about half of what his 2nd choice college costs per year ($18K vs. $35K), and his grades and test scores definitely were the biggest factor in being admitted ... so in effect, the academic achievement which gave him more options also reduced his college cost. I hope that makes some sense.
Good luck to you and your son!