Making a LAN app. What should I use ?

Hi ! I'm new here and totally new to scripting. I need to make a customerrelations database with some sort of messageboard. It all needs to be lowlevel, cuz the users hardly know anything of computers (kinda like me, but then even less).

I've been hearing lots of good stuff about PHP and MySQL (besides, both of em are installed on our server). It needs to be multi-user cuz people tend to make appointments on the same day and aren't supposed to make 2 appointments on the same hour right ?

How would I approach this project? I have database experience, but REALLY would like to try something else then Access. Don't mean to be offensive, but I dislike that program.

In the end when everything is running I want to make a Flash front since thats where my experience lies. If anyone has any ideas on this matter, or has done one before, I could really use the input ! Thanks in advance !