I am building a simple CMS for a website, Instead of having a simple texarea box I want it to have different buttons on it for the users to edit the code without knowing html or css. I would like it to be like Daniweb's Toolbar above the textbox on the site. how would I go about doing this

I am voting also for TinyMCE . I am using it a long time now and I must state that it is one of the finest projects in manner of customization.