Okay, here's what I think. If you feel as though you outline the problems that led to your resignation and that in doing so, those problems will be dealt with as a result, then outline the problem areas.
If you feel that regardless of what you say or tell them that it will not change anything then there is no need to go into detail and further alienate you from this group. I would do so, only if it would help provide results.
Here's my example that you can use without details-
Dear XXX,
I have enjoyed serving on the PTO for several years now and although I will miss it, I have personal obligations that will require my full attention.
I thank you for the opportunity to allow me to serve and should my situation change in the future, hope that I may be able to be involved again at that time.
When we decided to change meeting time, it was put up for a vote, not just a one person decision. It sounds like you have a lot on your plate. I was there two years ago when it seems like I had finally gotten to the point when I could help and then I was pregnant and going to school and got hurt and I couldn't help and I felt like I was never going to be able to get back into it so I didn't want to let go. In the end I just dropped everything I didn't have to do so I could focus on what I had to and after I had the baby, people where calling asking me to help again. I think you have your heart in the right place but you need to bodies to do what you want. It sounds like you do have the best interest of the school in mind because you accept that you aren't able to do what you need to and are stepping down because of it. I think just a simple statement telling that you aren't able to come to the meetings at the new time and so you would like to give someone else the oppurtunity to fulfill the requirements of the position. I would offer this to the President and the Principal. I know this is rough but I'm sure that with your education and new house and other volunteer duties that you will have enough stress to entertain you!
The irony of commitment is that it’s deeply liberating-in work, in play, in love. The act frees you from the tyranny of your internal critic, from the fear that likes to dress itself up and parade around as rational hesitation. To commit is to remove your head as the barrier to your life. --Anne Morris
I should have took the major hint last May. As soon as I got my class schedule I sent it to the pres. The understanding was work/class are high priorities for me. She changed the meetings on an evening when I had class. We have had 1 board meeting. I was able to attend the 1st general meeting, other members and my kids are keeping me informed on a few things. There is definately a major communication gap. Plus, I know this is extremely immature, but I have bitter feelings that she is getting to sub for the people I used too (I have been a sub aide for 4 years, she got on the list last year). We were friends and she heard me gripe constantly about how the new people on the list get to work more than those of us that had been on there for a while even the ones that are taking education classes. So then she got on the list and would throw it in my face when she got to work. We kinda got that cleared up, but it is still present. I will probably have to find a different job after we get moved in our house(currently under construction). Plus, this semester has been a bit overwhelming. I am supposed to be the vol. cooridinator also, I told them I would send them updates on what is going on, but I never know. She often announces that there will be enough volunteers for functions, I think that sends the wrong messege. I have no record of any of the committee meetings that have been held or anything. So if something went wrong because I am officially a board member, I am sure I would get dragged into the middle of it and I'd be totally clueless. She has a few favorite volunteers that she contacts quiet abit, I think one of them would be better suited for the responsiblities of this position. And that is the rest of the story. Ha Ha!
No, your letter doesn't have to be "XX" amount of words etc. You want out, period. yeah, is everything okay? But yeah, it's cool. "We" just are surprised.