Web Tables and php forms

I am completely stuck, and I am preying that someone will be able to help me. I have set up a php web form that allows one of my users to write columns for my site. This works great, I do a search and replace to replace /n with <br> because they don't know much about html. I have managed to get them into the habit of using bold, italics and underline tags, but now a few of them want to add tables and I have no idea how I can make this easy for them. Has anyone got any idea how I could allow them to do this, or perhaps know of a system that could be of some benefit, keeping in mind their minimal html expertise? Any help would be GREATLY appreciated. Peace