FCKEditor is a ccery cool WYSIWYG editor which allows you to type and format HTML. One downside is that this control does not currently have proper support for AJAX UpdatePanels in .NET.

After searching the net for very convoluted solutions to this very basic .NET need, I came across Dave Parslow's Website where he presents the following simple hack to get your FCKEditor working in update panels:

this.Page.ClientScript.RegisterOnSubmitStatement(

    this.GetType(),

    "AjaxHack",

    "for ( var i = 0; i < parent.frames.length; ++i ) if ( parent.frames[i].FCK ) parent.frames[i].FCK.UpdateLinkedField();"

    );