I'm trying to add tinyMCE instead of textarea for one of my options in my plugin with no luck so far. I tried this :
http://www.dbuggr.com/smallwei/add-wysiwyg-editor-tinymce-wordpress-plugin/
and this:
There seems to be some problem with styles as styles for tabs (HTML style/Visual style) dont work. Anybody knows about implementation that works 100% with WP 3.0 and up ?