Thanks :mrgreen:! The TinyMCE should meet what I want but unfortunately doesn't support Firefox (works well on IE). Previously I also found a few written in ASP.NET but my server do not support.

FCKeditor looks good, but it allow user to browse into the server when accessing files/images, which may be a security breach. I will download it and do some mod if possible.

Any other WYSIWYG online editors written in PHP or javascript? Anything as simple as one used in ebay listing would be great (require very little learning by users).