When the decision is made to transfer and you receive you're letter of acceptance to you're new school, when should you notify you're current coaching staff?

IMO, at the end of the season.

While you may have every intention of enrolling at the new school you havent yet.

Anything can happen between now and the end of the season that might influence your decision to transfer.

And the coaching staff is not going to notify you until the end of the season if they decided you werent in their future and to find another school.

Thank You. You actually answered another question. That was, when does the coaching staff notify players of scholarship renewal or not.

The ability to transfer, and play baseball, isn't a decision over which you have control.
If this is an NCAA school, the player needs to obtain a release from his current school/AD in order to be able to contact any other schools about baseball and in order to transfer and play. If this is DI to DI, you also have the additional complication of the new transfer rule and sitting out one year.
Hopefully the player has had no contact with the coaches at the new school or you have the release.
The way you have posted indicates you do not have a release, and have not asked for one, since the coaches don't know yet.
I would research those issues carefully before taking any steps/communications.

The transfer is D1 to JUCO. Does that make a difference?

It sure does. A release will not be needed and he will not need to sit out one year.
With those out of the way, there is not a good time to tell the coaches, but there are better times.
The better time is at the conclusion of the baseball season. In the meantime, he needs to give 110%.

Thank You. Had me worried for a minute. I thought we had done everything right. The part about 110%. I don't worry that.

The only uncertainty about transfering is he is eligible to play right away.

Many JUCO's require players to have taken a certain amount of credits in the prior qtr/semester to have eligiblity right away.

Your JUCO coach would be the one to verify this requirement and is usually not an issue if the player is taking a normal class load at his current school.

Another thing: if the player intends to eventuall return to DI and play to make sure he takes the right classes at the JUCO so they are transferable. In this way he will have maintained the necessary progress mandated by the NCAA toward graduation.

I'll have my son verify eligibility with the coach. I assume everything is in line. He has already spoke with the coach, who has talked with admissions and this is a top ranked JUCO who sends players on to D1's every year.

Im sure JUCO will work out just fine. It did for my son who went DI - Juco and will now return to DI.

Does anyone know the NCAA rules if a DI player wants to transfer to D2 can the D2 coaches be contacted by parents or another party?

INFbbmom,
The implications of a mistake here are pretty serious, so you should probably call the NCAA, and also ask for a confirmatory email if they say the contact is allowed.

However, my reading of the following rule is that any discussion by the new school with the parents would not be allowed.

From the D2 manual:
13.1.1.2 Four-Year College Prospective Student-Athletes. An athletics staff member or other representative of the institution’s athletics interests shall not make contact with the student-athlete of an NCAA or NAIA four-year collegiate institution, directly or indirectly, without first obtaining the written permission of the first institution’s athletics director (or an athletics administrator designated by the athletics director) to do so, regardless of who makes the initial contact. If permission is not granted, the second institution shall not encourage the transfer and shall not provide athletically related financial assistance to the student-athlete until the student-athlete has attended the second institution for one academic year. If permission is granted to contact the student-athlete, all applicable NCAA recruiting rules apply. (Revised: 1/10/91, 1/16/93, 1/11/94, 1/10/05 effective
8/1/05, 1/9/06)

The earlier question asked about a D1 player moving to DII. How about a DIII player transferring to a DII school. Is the same release required? The rule above suggests it is. Does anyone know for sure? Thanks.