I think I might be able to help out some on this since it's my dream to coach at the college level and I've had a few offers to do it as well.
First - CADad gave you some great advice but I don't think anything can really top Woody's advice. The things said about people at the college level can be very harsh but you have to learn how to roll with the punches.
Second - I do agree with CADad that you can surf through sites and see what their backgrounds are but overall it doesn't matter. Sometimes a school will post an opening and attach a certain degree to it due to possible teaching positions and / or other jobs with the college. They are looking for a coach first and can work with you on other things.
Third - he needs to understand that he will be very poor for a very long time until he can catch on with the bigger schools. That will take time and perseverence and taking on other jobs that will allow him to still coach baseball. It will take creative thinking to make this happen. I was offered an asst. job at a small school in Oakland about 5 years ago. I sent my resume to the school and about a month later I get a call from the head coach telling me I was going to have a phone interview with him and the AD. He coached me up on what was going to be asked and even told me how to answer some of the questions. I took that as a good sign. I had the phone interview and felt I did very well and the head coach called me about 4 days later. He said (and I'll never forget this conversation) "Coach, I would like to offer you the asst. coaching position at such and such university......but you would be crazy to take it." He said that the coaching job only paid $5000 for the season, no other type of job with the school, no type of free housing or any other help of any kind. He said giving up a well paying high school teaching job to move across the country without the promise of anything else would be crazy. He was right so I told him I would have to turn it down. He said he understood but this is the situation a new coach will have to face early on.
Fourth - this one is ridiculous but it is what it is - they really won't consider you unless you have college coaching on your resume. I heard this several times and I do but don't understand this. If I was your son or anybody for that matter don't take a high school coaching job out of college and think you can get back in.....unless you have some strong connections. I didn't have those connections and I gave up playing after two years because I got the opportunity to coach at a local high school. I made the mistake of thinking I could use the HS job to fast track back into college. Looking back that was dumb because the inroad really isn't there, you get used to a pretty good / fixed income and you start building up bills that need that income to pay off.
What I would do if I had it to do over is continue playing and when finished stay on at the school as some sort of grad asst. Then work upward from there because you now have asst. coach on the resume. Start networking and get to know people, work major college camps and get the job done on the field.
Fifth - check out these websites
http://naia.cstv.com/member-se...ntCoachPositions.htmthis one is for head / asst coaching jobs at NAIA schools
http://naia.cstv.com/member-se...tInternpositions.htmthis one is for grad asst. / intern positions at NAIA schools
http://ncaamarket.ncaa.org/job.../myaccount/index.cfmthis one is for the NCAA and you have to create some kind of account and then search for jobs you want. I haven't been on here in a few years so not real sure how it works anymore but should be easy to figure out.
Check out these websites to find jobs that are open and look at what they are looking for. Most Christian / religious based schools will want a statement of faith so be prepared for that when applying. I'm assuming your son is in HS so he doesn't need to worry about this step just yet but he can check it out on occasion to get a feel for how the jobs are posted.
Sixth - preferabbly play college baseball before transitioning to the coaching side. While it's not completely necessary to play in college to coach it does help. The speed of the college game is fast and if you know it before hand it can help as a coach. I played at a NAIA school and it's very close to the bottom of the ladder when it comes to baseball talent. I was pretty good in high school and the step to just NAIA school was pretty big. It helps to know the "feel" of the game.
If he doesn't get the opportunity to play then go to the baseball coach when he first steps foot on campus and tell him of his goal to coach. They can probably take him on as a manager and he can do the grunt work while watching how those guygs coach and pick up things. Then as he gets older and develops a stronger relationship with the staff start picking their brain on the how's, the why's and the what for's of coaching. He'll probably learn more from this than almost anything. Then move up to grad asst. and hopefully full asst. and then head coach.
Please understand I cannot say this is a surefire method to work. I never did this but looking back on how I did do things and how they didn't work out this is what I would do different. It may work and it may not plus each school / coaching staff is different.
Tell him I wish him luck but it's not all sunshines and rainbows like they show on the CWS. Almost all those guys started at the lowest rung and had to truly work to get to where they are. Your son probably knows this but he doesn't understand how tough it is to start out at the bottom.