Andy, Ill email you the code for this, provided it works. When youve put it on ur site (dont put a link to it yet though, so that no one can see it until ive checked it again), email it to me and ill make sure this works in youre frames. The code is pretty straight forward so you can look at it to change colours and stuff (ive put tags in saying "THIS IS THE CODE FOR LINKING COLOUR" etc so you can tell). You need to either create a graphic called "submitted.jpg" or save the one below (if u like it) and upload it to your server. People will see it when theyve sent you something using the form.
Now you need this image too, its what people see when theyve left part of the form blank. Please save it and upload as "required.jpg".