edit simple text file

Hello, I have a question that I was hoping somebody here could answer or atleast point me in the right direction. I maintain a series of mailing lists for our organization. Currently, I edit the distribution lists myself, but I would like to offload this administration to the departments themselves. Ideally, I could set up a web site that would let them edit the dist file themselves, and then save the changes. The php file would simply load up a text file from a fixed location, and then display it in a form. The user could then edit and save the file to the same location from where it was opened. Basically, I need a very simple text editor done in PHP. Unfortunately, when I search for “PHP text editor” I get development tools. Any help would be greatly appreciated, -Hitesh