He has not shown us his face in the manga or anime but he has shown us his eye (the left one I think) in the manga showing he has a sharingan. But to answer your question he probably wont for a long time (if at all) but you can get some ideas from the flashbacks of young Mandara Uchiha, who he claims to be.
To hide his face...and hide his sharingan and rinnegan
After he got his Rinnegan he has shown it the entire time. Before he had two Sharingans. It is more likely he wanted to hid his true identity, since he called himself Madara Uchiha a long time, but turned out to be somebody else.
Tobi :D
Ebay?
Tobi is a character from the manga and anime series Naruto. He is typically depicted as wearing a mask with a single hole for his right eye, covering his left eye with his hair. He is often seen wearing a black cloak with red clouds on it.
The first Tobi is kakashi's best friend obito the second Tobi is the founder of the hidden leaf village Madara Uchia
The face of Madara Uchiha.
Madara, Obito or Madara's brother.
i think it is Madara Uchiha because he fought with the First Hokage in the Valley of End but i'm not for sure though. no one really knows the question who is Tobi behind the mask
the boy is wearing a mask to cover his face
There are many masked men in Majora's Mask: - The one wearing the Keaton's Mask is Kafei. - The one wearing the Postman's Hat is Postman. - The one wearing Majora's Mask (the main antagonist in the game) is Skull Kid. - The one wearing Don Gero's Mask is a Goron, and is unnamed. - The one wearing the Stone Mask (the invisible soldier) is called Shiro.
Tobi only appears in the Shippuuden part, and he has a mask up until the war arc, where he is revealed to be *Spoiler! Do not read on if you haven't read the war arc and don't want to know who Tobi is!*Uchiha Obito, Kakashi's former teammate who was presumed dead.
here a link to a how to make a Tobi mask video... http://www.youtube.com/watch?v=4dywxM0bfmU
The one with the mask "Tobi" is not Uchiha Madara. Simple as that.