I've considered making it a plugin - I just haven't gotten around to actually writing it up yet (been too busy on the homefront) - but yeah, I have this simple little javascript that I attach to the wp-admin/edit-form-advanced.php (for posts) and wp-admin/edit-page-form.php. I put the text I want at the top that explains everything, each section has it's own little header list of links. For example, the last client I did this for had a lot of images she needed to float on the left and right side of her Pages. So I put in a link that said "images" right under the "Write Page" heading (before the quicktags) - so if she needed a reminder on how to utilize the"image" and "class" quicktags I had created for her, she just clicked the link. The instructions would pop out under the link on what to do. When she was done, she'd click the link again, and they'd fold right back up.
It's similar to the <!--more--> tag, but used in the admin area, I guess. It's a script I've had for a while and used on various sites for expanding divs (like when people need to buy stuff, and divs fold out based on their choice of payment - that kind of thing) and I just decided to implement it in the admin area for clients. Works really well.
Like I said, I have seriously considered writing it all up as a plugin, I just haven't gotten around to it. Plus, I don't know if anyone else really would *want* such a thing, you know? I see a few people ask for something similar every now and again, but I don't know if there really is a huge demand for such a thing.
But if you're interested in it, I'd be happy to email you the script and a little bit of instruction on how to do it. It's really pretty easy. (If you want it - you can go to my website and email me from the contact form :) )