42665 simple php sign up processor

Problem: I have a web form (html) that is used to sign people up for a class online. They fill out a form that has a few various fields. Course Date (from Drop Down), First Name, Department, Phone, Facility (Drop down also) and a few other fields. The information is emailed to us and we have to watch the amount of pages we get and close the class after say 20 people have emailed us. The major issue with this is if we arne't in the office we might get more than 20 signups and we can only have 20. What I need: A php script that inserts data into mysql database, then emails a form to let us know the person signed up with their information (fields from form - entire list shall be submitted after project accepted, not too manY) along with IP address. ALSO *** The script should check to see how many are signed up for the class and not allow the person to sign up if there are already20 persons signed up already. If their are 20 already signed up some sort of message should be displayed to let hte person know to select another class would be very helpful. Bonus -- if the drop downs could be dynamic and know if there are 20 people signed up for the class, it would not show the course in the drop down. This isn't that big of a deal, but would be need to have if it wouldn't raise the price too much. Must have, well functioning script, with comments etc for editing in the future. Would want to see a full functioning sample. We pay fast and enjoy working with speedy professionalions. Let's get this project started.