TinyMCE visual editor custom

Hi all,

I would like to add a button to the visual editor of wordpress by creating a plugin.
One click on this button will display a inputbox which request a string.
This string have to be embeded by html code and have to be added in the post(editor).
Does anybody knows how can i do it ?
I seek about 2 weeks tro create a plugin like it…but i don’t manage to success my work :-(.
So i call everybody can help me.
Regards !