using files in php

Hello, I have created a mail system on my webpage, but I have a problem. I use a form to create the E-Mail (I create it), and the e-mail will be mailed to all people in a Mysql database. This works. But: the data in the form can only be 1024 chars long. I pass the data with a submit button. Is it possible to do this with a form, or do I have to use a file. for example: I create a file mail.txt and the php file reads this and mails it to everyone in the database??? Help, I have 500 members and I would like to work with this system... Greetings Emiel Theloosen The Netherlands emielt@chello.nl